Azure99/stackoverflow-qa-top-300k · Datasets at Hugging Face

4,194,439

Sending commands to server via JSch shell channel

I can't figure it out how I can send commands via JSch shell channel. I do this, but it doesn't work: <pre><code>JSch shell = new JSch(); String command = "cd home/s/src"; Session session = shell.getSession(username, host, port); MyUserInfo ui = new MyUserInfo(); ui.setPassword(password); session.setUserInfo(ui); session.connect(); channel = session.openChannel("shell"); fromServer = new BufferedReader(new InputStreamReader(channel.getInputStream())); toServer = channel.getOutputStream(); channel.connect(); toServer.write((command + "\r\n").getBytes()); toServer.flush(); </code></pre> and then I read input like this: <pre><code>StringBuilder builder = new StringBuilder(); int count = 0; String line = ""; while(line != null) { line = fromServer.readLine(); builder.append(line).append("\n"); if (line.endsWith(".") || line.endsWith(">")){ break; } } String result = builder.toString(); ConsoleOut.println(result); </code></pre>

7,503,273

10

5

null

2010-11-16 13:09:00.997 UTC

11

2021-10-27 22:19:27.093 UTC

2014-11-14 07:51:25.633 UTC

null

850,848

null

493,575

null

1

27

java|ssh|jsch

82,019

If it hangs at <code>readLine()</code> that means either your "while" is never ending (might be unlikely considering your code), or, <code>readLine()</code> is waiting for its source, namely the <code>IOstream</code> blocks the thread cause <code>available()!=true</code>. I can't quite troubleshoot your code without seeing your debug info. But as an advice, have you tried <code>PipedIntputStream</code>? The idea is to pipe your console input to "your" output so that you can "write" it. To implement this, you need to initialize the in/out-put. <pre><code>InputStream in = new PipedInputStream(); PipedOutputStream pin = new PipedOutputStream((PipedInputStream) in); /**...*/ channel.setInputStream(in); channel.connect(); /** ...*/ pin.write(myScript.getBytes()); </code></pre> The same goes to your question, how to read console output. <pre><code>PipedInputStream pout = new PipedInputStream((PipedOutputStream) out); /** * ... */ BufferedReader consoleOutput = new BufferedReader(new InputStreamReader(pout)); consoleOutput.readLine(); </code></pre> And again, if you are not sure how many lines to read and thus want to use "while", make sure you do something inside while to prevent 1) busy-waiting 2) ending-condition. Example: <pre><code>while(!end) { consoleOutput.mark(32); if (consoleOutput.read()==0x03) end = true;//End of Text else { consoleOutput.reset(); consoleOutput.readLine(); end = false; } } </code></pre>

4,099,975

Difference between a module, library and a framework

In popular programming speak, what is the difference between these terms and what are the overlaps? Any related terms I'm missing out?

4,101,270

11

4

null

2010-11-04 18:32:09.72 UTC

84

2021-12-28 18:02:22.277 UTC

null

103,955

null

1

90

frameworks|module

55,258

All three of those provide functionality. However, there are important differences. A library is just a collection of related functionality. Nothing more, but also nothing less. The defining characteristic of a library is that you are in control, you call the library. The defining characteristic of a framework is Inversion of Control. The framework calls you, not the other way round. (This is known as the Hollywood Principle: "Don't call us, we'll call you.") The framework is in control. The flow of control and the flow of data is managed by the framework. You can think of it this way: in both cases, you have an application, and this application has holes in it, where code has been left out, and these holes need to be filled in. The difference between a library and a framework is <ul> <li>who writes the application,</li> <li>what are the holes and</li> <li>who fills in the holes.</li> </ul> With a library, you write the application, and you leave out the boring details, which gets filled in by a library. With a framework, the framework writer writes the application, and leaves out the interesting details, which you fill in. This can be a little confusing at times, because the framework itself might also contain boring details, that the framework author filled in with libraries, the parts that you write might contain boring details, that you fill in with libraries, and the framework might provide a set of bundled libraries that either work well with the framework or that are often needed in conjunction with the framework. For example, you might use an XML generator library when writing a web application using a web framework, and that XML library might have been provided by the framework or even be an integral part of it. That doesn't mean, however, that there is no distinction between a library and a framework. The distinction is very clear: Inversion of Control is what it's all about. The defining characteristic of a module is information hiding. A module has an interface, which explicitly, but abstractly specifies both the functionality it provides as well as the functionality it depends on. (Often called the exported and imported functionality.) This interface has an implementation (or multiple implementations, actually), which, from the user of a module are a black box. Also, a library is a collection of related functionality, whereas a module only provides a single piece of functionality. Which means that, if you have a system with both modules and libraries, a library will typically contain multiple modules. For example, you might have a collections library which contains a <code>List</code> module, a <code>Set</code> module and a <code>Map</code> module. While you can certainly write modules without a module system, ideally you want your modules to be separately compilable (for languages and execution environments where that notion even makes sense), separately deployable, and you want module composition to be safe (i.e. composing modules should either work or trigger an error before runtime, but never lead to an runtime error or unexpected behavior). For this, you need a module system, like Racket's units, Standard ML's modules and functors or Newspeak's top-level classes. So, let's recap: <ul> <li>library: collection of related functionality</li> <li>framework: Inversion of Control</li> <li>module: abstract interface with explicit exports and imports, implementation and interface are separate, there may be multiple implementations and the implementation is hidden</li> </ul>

14,628,927

Writing a highly scalable TCP/IP server in C# 5 with the async/await pattern?

I'm tasked with designing a fairly simple TCP/IP server that must accept connections from multiple clients. It needs to be written in C#, and I'm using .NET 4.5. That said, I'm not sure what is the current "state of the art" for TCP/IP server/client scalability in .NET 4.5. I did see this post: <a href="https://stackoverflow.com/questions/869744/how-to-write-a-scalable-tcp-ip-based-server">How to write a scalable Tcp/Ip based server</a>. But that relates to .NET 2.0 and 3.5 and makes no mention of the async/await pattern. I am capable of writing a server the "old way"... but I want to know what the "new way" is. <ul> <li>What is the best way to use the new Async methods on Socket, TcpClient or TcpListener to create a scalable server in C#?</li> <li>Do the new Async methods leverage I/O Completion Ports?</li> <li>Is rolling your own Socket listener more efficient, or are the TcpListener/TcpClient classes pretty good now?</li> </ul> EDIT: Additional questions.

14,629,612

1

12

null

2013-01-31 15:09:59.323 UTC

16

2020-04-06 03:05:10.873 UTC

2017-05-23 12:09:52.997 UTC

null

-1

null

135,786

null

1

27

c#|.net|sockets|async-await

21,377

<blockquote> What is the best way to use the new Async methods on Socket, TcpClient or TcpListener to create a scalable server in C#? </blockquote> There aren't any new <code>async</code> methods on <code>Socket</code>; the methods named <code>*Async</code> on <code>Socket</code> are a special set of APIs to reduce memory usage. <code>TcpClient</code> and <code>TcpListener</code> did get some new <code>async</code> methods. If you want the best scalability, you're probably best using <a href="https://devblogs.microsoft.com/pfxteam/awaiting-socket-operations/" rel="nofollow noreferrer">Stephen Toub's custom awaiters for <code>Socket</code></a>. If you want the easiest to code, you're probably better off using <code>TcpClient</code> and <code>TcpListener</code>. <blockquote> Do the new Async methods leverage I/O Completion Ports? </blockquote> Yes, just like most of the other asynchronous APIs in the BCL. AFAIK, the <code>Stream</code> class is the only one that may possibly not use the IOCP; all other <code>*Begin</code>/<code>*End</code>/<code>*Async</code> methods use the IOCP. <blockquote> Is rolling your own Socket listener more efficient, or are the TcpListener/TcpClient classes pretty good now? </blockquote> The classes are pretty good as they are. Stephen Toub has a <a href="https://devblogs.microsoft.com/pfxteam/awaiting-socket-operations/" rel="nofollow noreferrer">blog post</a> that is a bit more efficient in terms of memory use.

14,628,576

Passing an JSON array to MVC Web API via GET

I know there are tons of answers for this topic, but couldn't find the solution to my issue. I have an ASP.NET MVC Web API that looks like this: <pre><code> [HttpGet] public IList<Country> GetCountryList(List<long> idList) </code></pre> And I've tried calling it like this: <pre><code> $.ajax({ dataType: "json", data: JSON.stringify({idList: listOfIds}), type: "GET", url: "api/v1/util/CountryList", success: function (result) { alert(result); } }); </code></pre> The URL then looks like this: <pre><code>https://localhost/supertext/api/v1/util/CountryList?{%22idList%22:[46,14,62,83,120]} </code></pre> Alternative: <pre><code> $.ajax({ dataType: "json", data: { idList: JSON.stringify(listOfIds), } type: "GET", url: "api/v1/util/CountryList", success: function (result) { alert(result); } }); </code></pre> URL: <pre><code>https://localhost/supertext/api/v1/util/CountryList?idList=%5B46%2C14%2C62%2C83%2C120%5D </code></pre> Both methods don't work. Do I really have to send and receive it as a string or use POST?

14,628,736

2

0

null

2013-01-31 14:51:28.09 UTC

10

2018-04-27 12:26:59.447 UTC

null

375,192

null

1

28

jquery|asp.net-mvc|json|asp.net-web-api

46,417

No, don't try to be sending JSON in a GET request. Use JSON with other verbs which have body, such as POST and PUT. Do it the standard way, by decorating your action parameter with the <code>[FromUri]</code> attribute: <pre><code>public IList<Country> GetCountryList([FromUri] List<long> idList) { ... } </code></pre> and then just trigger the AJAX request: <pre><code>$.ajax({ url: 'api/v1/util/CountryList', type: 'GET', data: { idList: [1, 2, 3] }, traditional: true, success: function (result) { console.log(JSON.stringify(result)); } }); </code></pre> Further recommended reading for you about how the model binding in the Web API works: <a href="http://www.asp.net/web-api/overview/working-with-http/sending-html-form-data,-part-1" rel="noreferrer">http://www.asp.net/web-api/overview/working-with-http/sending-html-form-data,-part-1</a>

14,359,926

Send HTTP request from PHP without waiting for response?

I want to have an HTTP GET request sent from PHP. Example: <pre><code>http://tracker.example.com?product_number=5230&price=123.52 </code></pre> The idea is to do server-side web-analytics: Instead of sending tracking information from JavaScript to a server, the server sends tracking information directly to another server. Requirements: <ul> <li>The request should take as little time as possible, in order to not noticeably delay processing of the PHP page.</li> <li>The response from the <code>tracker.example.com</code> does not need to be checked. As examples, some possible responses from <code>tracker.example.com</code>: <ul> <li>200: That's fine, but no need to check that.</li> <li>404: Bad luck, but - again - no need to check that.</li> <li>301: Although a redirect would be appropriate, it would delay processing of the PHP page, so don't do that.</li> </ul> In short: All responses can be discarded.</li> </ul> Ideas for solutions: <ul> <li>In a now deleted answer, someone suggested calling command line <a href="http://en.wikipedia.org/wiki/CURL">curl</a> from PHP in a shell process. This seems like a good idea, only that I don't know if forking a lot of shell processes under heavy load is a wise thing to do.</li> <li>I found <a href="http://code.google.com/p/php-ga/">php-ga</a>, a package for doing server-side Google Analytics from PHP. On the project's page, it is mentioned: "Can be configured to [...] use non-blocking requests." So far I haven't found the time to investigate what method php-ga uses internally, but this method could be it!</li> </ul> In a nutshell: What is the best solution to do generic server-side tracking/analytics from PHP.

14,668,762

10

14

null

2013-01-16 13:48:53.39 UTC

15

2020-07-15 16:27:36.94 UTC

2013-01-30 20:07:26.993 UTC

null

282,729

null

282,729

null

1

49

php|http|curl|server-side|web-analytics

58,168

Unfortunately PHP by definition is blocking. While this holds true for the majority of functions and operations you will normally be handling, the current scenario is different. The process which I like to call <a href="http://www.coretechnologies.com/products/http-ping/">HTTP-Ping</a>, requires that you only touch a specific URI, forcing the specific server to boot-strap it's internal logic. Some functions allow you to achieve something very similar to this HTTP-ping, by not waiting for a response. Take note that the process of pinging an url, is a two step process: <ol> <li>Resolve the DNS</li> <li>Making the request</li> </ol> While making the request should be rather fast once the DNS is resolved and the connection is made, there aren't many ways of making the DNS resolve faster. Some ways of doing an http-ping are: <ol> <li><a href="http://www.php.net/manual/en/ref.curl.php">cURL</a>, by setting CONNECTION_TIMEOUT to a low value</li> <li><a href="http://php.net/manual/en/function.fsockopen.php">fsockopen</a> by closing immediately after writing</li> <li><a href="http://php.net/manual/en/function.stream-socket-client.php">stream_socket_client</a> (same as fsockopen) and also adding <code>STREAM_CLIENT_ASYNC_CONNECT</code></li> </ol> While both <code>cURL</code> and <code>fsockopen</code> are both blocking while the DNS is being resolved. I have noticed that fsockopen is significantly faster, even in worst case scenarios. <code>stream_socket_client</code> on the other hand should fix the problem regarding DNS resolving and should be the optimal solution in this scenario, but I have not managed to get it to work. One final solution is to start another thread/process that does this for you. Making a system call for this should work, but also <a href="http://php.net/manual/en/function.pcntl-fork.php">forking</a> the current process should do that also. Unfortunately both are not really safe in applications where you can't control the environment on which PHP is running. System calls are more often than not blocked and pcntl is not enabled by default.

23,070,822

Angular $scope.$apply vs $timeout as a safe $apply

I'm trying to better understand the nuances of using the $timeout service in Angular as a sort of "safe $apply" method. Basically in scenarios where a piece of code could run in response to either an Angular event or a non-angular event such as jQuery or some standard DOM event. As I understand things: <ol> <li>Wrapping code in $scope.$apply works fine for scenarios where you aren't already in a digest loop (aka. jQuery event) but will raise an error if a digest is in progress</li> <li>Wrapping code in a $timeout() call with no delay parameter works whether already in a digest cycle or not</li> </ol> Looking at Angular source code, it looks like $timeout makes a call to $rootScope.$apply(). <ol> <li>Why doesn't $timeout() also raise an error if a digest cycle is already in progress?</li> <li>Is the best practice to use $scope.$apply() when you know for sure that a digest won't already be in progress and $timeout() when needing it to be safe either way?</li> <li>Is $timeout() really an acceptable "safe apply", or are there gotchas?</li> </ol> Thanks for any insight.

23,073,968

3

0

null

2014-04-14 21:30:53.537 UTC

22

2015-07-27 10:44:53.207 UTC

null

20,489

null

1

70

angularjs|scope

30,826

<blockquote> Looking at Angular source code, it looks like $timeout makes a call to $rootScope.$apply(). <ul> <li>Why doesn't $timeout() also raise an error if a digest cycle is already in progress?</li> </ul> </blockquote> <code>$timeout</code> makes use of an undocumented Angular service <code>$browser</code>. Specifically it uses <code>$browser.defer()</code> that defers execution of your function asynchronously via <code>window.setTimeout(fn, delay)</code>, which will always run outside of Angular life-cycle. Only once <code>window.setTimeout</code> has fired your function will <code>$timeout</code> call <code>$rootScope.$apply()</code>. <blockquote> <ul> <li>Is the best practice to use $scope.$apply() when you know for sure that a digest won't already be in progress and $timeout() when needing it to be safe either way?</li> </ul> </blockquote> I would say so. Another use case is that sometimes you need to access a $scope variable that you know will only be initialized after digest. Simple example would be if you want to set a form's state to dirty inside your controller constructor (for whatever reason). Without $timeout the <code>FormController</code> has not been initialized and published onto $scope, so wrapping <code>$scope.yourform.setDirty()</code> inside $timeout ensures that <code>FormController</code> has been initialized. Sure you can do all this with a directive without $timeout, just giving another use case example. <blockquote> <ul> <li>Is $timeout() really an acceptable "safe apply", or are there gotchas?</li> </ul> </blockquote> It should always be safe, but your go to method should always aim for $apply() in my opinion. The current Angular app I'm working on is fairly large and we've only had to rely on $timeout once instead of $apply().

47,174,686

pyspark Window.partitionBy vs groupBy

Lets say I have a dataset with around 2.1 billion records. It's a dataset with customer information and I want to know how many times they did something. So I should group on the ID and sum one column (It has 0 and 1 values where the 1 indicates an action). Now, I can use a simple <code>groupBy</code> and <code>agg(sum)</code> it, but to my understanding this is not really efficient. The <code>groupBy</code> will move around a lot of data between partitions. Alternatively, I can also use a Window function with a <code>partitionBy</code> clause and then sum the data. One of the disadvantage is that I'll then have to apply an extra filter cause it keeps all the data. And I want one record per ID. But I don't see how this Window handles the data. Is it better than this groupBy and sum. Or is it the same?

47,177,002

1

0

null

2017-11-08 08:20:18.68 UTC

8

2017-11-08 10:17:37.383 UTC

2017-11-08 08:38:08.287 UTC

null

7,224,597

null

3,170,699

null

1

13

python|apache-spark|pyspark|apache-spark-sql

9,339

As far as I know, when working with spark DataFrames, the <code>groupBy</code> operation is optimized via <a href="https://databricks.com/blog/2015/04/13/deep-dive-into-spark-sqls-catalyst-optimizer.html" rel="noreferrer">Catalyst</a>. The <code>groupBy</code> on DataFrames is unlike the <code>groupBy</code> on RDDs. For instance, the <code>groupBy</code> on DataFrames performs the aggregation on partitions first, and then shuffles the aggregated results for the final aggregation stage. Hence, only the reduced, aggregated results get shuffled, not the entire data. This is similar to <code>reduceByKey</code> or <code>aggregateByKey</code> on RDDs. See this related <a href="https://stackoverflow.com/questions/32902982/dataframe-groupby-behaviour-optimization">SO-article</a> with a nice example. In addition, see slide 5 in this <a href="https://de.slideshare.net/databricks/a-deep-dive-into-spark-sqls-catalyst-optimizer-with-yin-huai" rel="noreferrer">presentation</a> by Yin Huai which covers the benefits of using DataFrames in conjunction with Catalyst. Concluding, I think you're fine employing <code>groupBy</code> when using spark DataFrames. Using <code>Window</code> does not seem appropriate to me for your requirement.

42,902,130

Azure Keyvault - "Operation "list" is not allowed by vault policy" but all permissions are checked

I am accessing KeyVault with .NET client with an AAD application. Although all permissions under secrets are enabled for this AAD app (screenshot below) I am getting "The operation "List" is not enabled in this key vault's access policy" if I navigate to the Secret panel. I would like to be able to set the permissions via the AAD application and so using Powershell wouldn't be an option. If I set the permissions via Powershell - it does work. How I'm creating my access policies: <pre><code> var accessPolicy = new AccessPolicyEntry { ApplicationId = app, ObjectId = Obid, PermissionsRawJsonString = "{ \"keys\": [ \"all\" ], \"secrets\": [ \"all\" ], \"certificates\": [ \"all\" ] }", TenantId = ten, }; return accessPolicy; </code></pre> which gives me <a href="https://i.stack.imgur.com/F9nsU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/F9nsU.png" alt="enter image description here"></a> Then the list error appears and so I have to use <pre><code>Set-AzureRmKeyVaultAccessPolicy -VaultName vaultname -ResourceGroupName location -ObjectId obid -PermissionsToKeys all -PermissionsToSecrets all </code></pre> That will get rid of the error but I would much prefer a solution so I can work with the .NET SDK to resolve.

42,948,221

3

0

null

2017-03-20 11:13:16.363 UTC

null

2020-07-15 13:49:41.373 UTC

null

4,352,619

null

1

26

c#|.net|powershell|azure|azure-keyvault

44,228

After ages of trying to sort this issue - the problem was in the access policies code. When a user is registered in the code - it associates itself with the app ID. The app ID is the problem as it thinks that the user is an application AND a user. The tell-tale sign of this is if you go into the portal, then "Access Policy" on a Keyvault and it'll say Application + User underneath. If you try and add a user (that is already on the list) - it will add the second user - so you'll have 2 of the same. So all that's needed is to: <pre><code> var accessPolicy = new AccessPolicyEntry { ApplicationId = app, // Delete this line ObjectId = Obid, PermissionsRawJsonString = "{ \"keys\": [ \"all\" ], \"secrets\": [ \"all\" ], \"certificates\": [ \"all\" ] }", TenantId = ten, }; return accessPolicy; </code></pre> The Microsoft documentation can be vague at times and I believe this is one of them.

56,336,234

Build Fail Sphinx Error contents.rst not found

I follow the instructions on read the docs but I get this error: <blockquote> bash Sphinx error: master file /home/docs/checkouts/readthedocs.org/user_builds/mybinders/checkouts/latest/docs/source/contents.rst not found </blockquote> Do have to you the read the docs yaml file?

56,448,499

2

0

null

2019-05-28 06:32:56.457 UTC

7

2020-10-07 07:55:59.753 UTC

2019-05-28 10:45:46.423 UTC

null

6,592,881

null

8,535,721

null

1

51

read-the-docs

9,649

If you have your own <code>conf.py</code> file, it overrides Read the Doc's default <code>conf.py</code>. By default, Sphinx expects the master doc to be <code>contents</code>. Read the Docs will set master doc to <code>index</code> instead (or whatever it is you have specified in your settings). Try adding this to your <code>conf.py</code>: <pre><code>master_doc = 'index' </code></pre> For more information, check out this issue: <a href="https://github.com/rtfd/readthedocs.org/issues/2569" rel="noreferrer">https://github.com/rtfd/readthedocs.org/issues/2569</a>

41,723,018

JetBrains Rider EAP on Linux - Solution load failed: MsBuild not found

Just installed the latest version of Rider EAP (163.12057) and tried to create a new solution. In my Solution Explorer its shows my Solution and (load failed). In the Event Log window I get the error message: <blockquote> Solution 'FirstSolution' load failed: MsBuild not found on this machine </blockquote> Any ideas on how I can solve this loading problem? Thanks in advance!

41,724,349

3

1

null

2017-01-18 15:17:20.373 UTC

2

2022-02-19 06:55:31.667 UTC

2017-01-18 19:07:25.92 UTC

null

783,119

null

4,520,219

null

1

28

msbuild|jetbrains-ide|rider|failed-to-load-viewstate

14,662

I managed to solve the loading error. I was missing Mono and found out through this thread <a href="https://rider-support.jetbrains.com/hc/en-us/community/posts/207243685-Unity3D-support?page=2#comments" rel="noreferrer">here</a> that Rider currently needs Mono 4.6.2. I followed <a href="http://www.mono-project.com/docs/getting-started/install/linux/#usage" rel="noreferrer">this</a> guide to install Mono. <pre><code>sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list sudo apt-get update sudo apt-get install mono-devel sudo apt-get install mono-complete </code></pre> I hope this will help someone else. UPDATE: Asp.Net Core if you'll be using Asp.Net Core, and encounter error about missing <code>xsp.exe</code> you might need to install <code>mono-xsp4</code> with this command <code>sudo apt-get install mono-xsp4</code>

3,099,234

jstl foreach omit an element in last record

trying to use this jstl to formulate a json string, how can i make the segment not to put a comma in the end of the last record? note the comma in the end <pre><code><c:forEach items="${fileList}" var="current"> { id:1001,data:["<c:out value="${current.fileName}" />" , "<c:out value="${current.path}" />" , "<c:out value="${current.size}" />" , "<c:out value="${current.type}" />"] }, </c:forEach> </code></pre>

3,101,346

3

1

null

2010-06-23 05:56:14.787 UTC

13

2013-09-19 19:19:23.203 UTC

2013-09-19 19:18:17.31 UTC

null

4,311

null

355,974

null

1

68

jsp|jstl

68,191

Just use <a href="http://java.sun.com/javaee/5/docs/api/javax/servlet/jsp/jstl/core/LoopTagStatus.html#isLast()" rel="noreferrer"><code>LoopTagStatus#isLast()</code></a>. <pre><code><c:forEach items="${fileList}" var="current" varStatus="loop"> { id: 1001, data: [ "<c:out value="${current.fileName}" />", "<c:out value="${current.path}" />", "<c:out value="${current.size}" />", "<c:out value="${current.type}" />" ] }<c:if test="${!loop.last}">,</c:if> </c:forEach> </code></pre> You can also use the conditional operator in EL instead of <code><c:if></code>: <pre><code> ${!loop.last ? ',' : ''} </code></pre>

3,028,899

What is the difference between remote procedure call and web service?

Is there any clear definition of RPC and Web Service? A quick wikipedia search shows: <blockquote> RPC: Remote procedure call (RPC) is an Inter-process communication technology that allows a computer program to cause a subroutine or procedure to execute in another address space (commonly on another computer on a shared network) without the programmer explicitly coding the details for this remote interaction. Web Service: Web services are typically application programming interfaces (API) or web APIs that are accessed via Hypertext Transfer Protocol and executed on a remote system hosting the requested services. Web services tend to fall into one of two camps: Big Web Services[1] and RESTful Web Services. </blockquote> I am not quite clear what the real difference between the two things. It seems that one thing could belong to RPC and is kind of web service at the same time. Is Web Service a higher level representation of RPC?

3,028,917

4

0

2010-06-12 13:57:08.527 UTC

2010-06-12 13:54:01.417 UTC

22

2020-04-23 06:26:38.603 UTC

2020-02-14 18:51:41.98 UTC

null

2,094,956

null

166,482

null

1

86

web-services|rpc

54,691

<blockquote> Is Web Service a higher level representation of RPC? </blockquote> Yes, it is. A web service is a specific implementation of RPC. At its lowest level, Web Service connects to the Socket, using the HTTP protocol, to negotiate sending a payload that is executed in a remote space (remote space can be the same computer). All these remote call abstractions, at its core, are RPCs.

3,078,081

Setting global styles for Views in Android

Let's say I want all the <code>TextView</code> instances in my app to have <code>textColor="#ffffff"</code>. Is there a way to set that in one place instead of setting it for each <code>TextView</code>?

3,166,865

4

2

null

2010-06-20 03:07:55.35 UTC

48

2019-05-12 08:05:49.713 UTC

2016-04-12 20:16:10.86 UTC

null

1,176,870

null

200,145

null

1

139

android

100,194

Actually, you can set a default style for TextViews (and most other built-in widgets) without needing to do a custom java class or setting the style individually. If you take a look in <a href="https://github.com/android/platform_frameworks_base/blob/master/core/res/res/values/themes.xml" rel="noreferrer"><code>themes.xml</code></a> in the Android source, you will see a bunch of attributes for the default style for various widgets. The key is the <code>textViewStyle</code> (or <code>editTextStyle</code>, etc.) attribute which you override in your custom theme. You can override these in the following way: Create a <code>styles.xml</code>: <pre><code><?xml version="1.0" encoding="utf-8"?> <resources> <style name="MyTheme" parent="android:Theme"> <item name="android:textViewStyle">@style/MyTextViewStyle</item> </style> <style name="MyTextViewStyle" parent="android:Widget.TextView"> <item name="android:textColor">#F00</item> <item name="android:textStyle">bold</item> </style> </resources> </code></pre> Then just apply that theme to your application in <code>AndroidManifest.xml</code>: <pre><code><application […] android:theme="@style/MyTheme">… </code></pre> And all your text views will default to the style defined in <code>MyTextViewStyle</code> (in this instance, bold and red)! This was tested on devices from API level 4 onward and seems to work great.

38,722,202

How do I change the number of decimal places on axis labels in ggplot2?

Specifically, this is in a facet_grid. Have googled extensively for similar questions but not clear on the syntax or where it goes. What I want is for every number on the y-axes to have two digits after the decimal, even if the trailing one is 0. Is this a parameter in scale_y_continuous or element_text or...? <pre><code>row1 <- ggplot(sector_data[sector_data$sector %in% pages[[x]],], aes(date,price)) + geom_line() + geom_hline(yintercept=0,size=0.3,color="gray50") + facet_grid( ~ sector) + scale_x_date( breaks='1 year', minor_breaks = '1 month') + scale_y_continuous( labels = ???) + theme(panel.grid.major.x = element_line(size=1.5), axis.title.x=element_blank(), axis.text.x=element_blank(), axis.title.y=element_blank(), axis.text.y=element_text(size=8), axis.ticks=element_blank() ) </code></pre>

38,722,547

4

0

null

2016-08-02 13:43:40.673 UTC

25

2022-03-24 14:13:10.267 UTC

null

1,586,901

null

1

75

r|ggplot2

97,883

From the help for <code>?scale_y_continuous</code>, the argument 'labels' can be a function: <blockquote> labels One of: <ul> <li>NULL for no labels</li> <li>waiver() for the default labels computed by the transformation object</li> <li>A character vector giving labels (must be same length as breaks)</li> <li>A function that takes the breaks as input and returns labels as output</li> </ul> </blockquote> We will use the last option, a function that takes <code>breaks</code> as an argument and returns a number with 2 decimal places. <pre><code>#Our transformation function scaleFUN <- function(x) sprintf("%.2f", x) #Plot library(ggplot2) p <- ggplot(mpg, aes(displ, cty)) + geom_point() p <- p + facet_grid(. ~ cyl) p + scale_y_continuous(labels=scaleFUN) </code></pre> <a href="https://i.stack.imgur.com/1205q.png" rel="noreferrer"><img src="https://i.stack.imgur.com/1205q.png" alt="enter image description here"></a>

40,554,106

Read excel sheet with multiple header using Pandas

I have an excel sheet with multiple header like: <pre><code>_________________________________________________________________________ ____|_____| Header1 | Header2 | Header3 | ColX|ColY |ColA|ColB|ColC|ColD||ColD|ColE|ColF|ColG||ColH|ColI|ColJ|ColDK| 1 | ds | 5 | 6 |9 |10 | ....................................... 2 | dh | .......................................................... 3 | ge | .......................................................... 4 | ew | .......................................................... 5 | er | .......................................................... </code></pre> Now here you can see that first two columns do not have headers they are blank but other columns have headers like Header1, Header2 and Header3. So I want to read this sheet and merge it with other sheet with similar structure. I want to merge it on first column 'ColX'. Right now I am doing this: <pre><code>import pandas as pd totalMergedSheet = pd.DataFrame([1,2,3,4,5], columns=['ColX']) file = pd.ExcelFile('ExcelFile.xlsx') for i in range (1, len(file.sheet_names)): df1 = file.parse(file.sheet_names[i-1]) df2 = file.parse(file.sheet_names[i]) newMergedSheet = pd.merge(df1, df2, on='ColX') totalMergedSheet = pd.merge(totalMergedSheet, newMergedSheet, on='ColX') </code></pre> But I don't know its neither reading columns correctly and I think will not return the results in the way I want. So, I want the resulting frame should be like: <pre><code>________________________________________________________________________________________________________ ____|_____| Header1 | Header2 | Header3 | Header4 | Header5 | ColX|ColY |ColA|ColB|ColC|ColD||ColD|ColE|ColF|ColG||ColH|ColI|ColJ|ColK| ColL|ColM|ColN|ColO||ColP|ColQ|ColR|ColS| 1 | ds | 5 | 6 |9 |10 | .................................................................................. 2 | dh | ................................................................................... 3 | ge | .................................................................................... 4 | ew | ................................................................................... 5 | er | ...................................................................................... </code></pre> Any suggestions please. Thanks.

40,555,989

1

0

null

2016-11-11 18:33:34.12 UTC

15

2021-05-28 07:54:40.17 UTC

null

5,453,723

null

1

38

python|excel|pandas|dataframe

69,555

[See comments for updates and corrections] Pandas already has a function that will read in an entire Excel spreadsheet for you, so you don't need to manually parse/merge each sheet. Take a look <a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.read_excel.html" rel="noreferrer">pandas.read_excel()</a>. It not only lets you read in an Excel file in a single line, it also provides options to help solve the problem you're having. Since you have subcolumns, what you're looking for is <a href="http://pandas.pydata.org/pandas-docs/stable/advanced.html" rel="noreferrer">MultiIndexing</a>. By default, pandas will read in the top row as the sole header row. You can pass a <code>header</code> argument into <code>pandas.read_excel()</code> that indicates how many rows are to be used as headers. In your particular case, you'd want <code>header=[0, 1]</code>, indicating the first two rows. You might also have multiple sheets, so you can pass <code>sheetname=None</code> as well (this tells it to go through all sheets). The command would be: <pre><code>df_dict = pandas.read_excel('ExcelFile.xlsx', header=[0, 1], sheetname=None) </code></pre> This returns a dictionary where the keys are the sheet names, and the values are the DataFrames for each sheet. If you want to collapse it all into one DataFrame, you can simply use pandas.concat: <pre><code>df = pandas.concat(df_dict.values(), axis=0) </code></pre>

40,360,936

graphql-go : Use an Object as Input Argument to a Query

I'm attempting to pass an object as an argument to a query (rather than a scalar). From the docs it seems that this should be possible, but I can't figure out how to make it work. I'm using graphql-go, here is the test schema: <pre><code>var fileDocumentType = graphql.NewObject(graphql.ObjectConfig{ Name: "FileDocument", Fields: graphql.Fields{ "id": &graphql.Field{ Type: graphql.String, Resolve: func(p graphql.ResolveParams) (interface{}, error) { if fileDoc, ok := p.Source.(data_format.FileDocument); ok { return fileDoc.Id, nil } return "", nil }, }, "tags": &graphql.Field{ Type: graphql.NewList(tagsDataType), Args: graphql.FieldConfigArgument{ "tags": &graphql.ArgumentConfig{ Type: tagsInputType, }, }, Resolve: func(p graphql.ResolveParams) (interface{}, error) { fmt.Println(p.Source) fmt.Println(p.Args) if fileDoc, ok := p.Source.(data_format.FileDocument); ok { return fileDoc.Tags, nil } return nil, nil }, }, }, }) </code></pre> And the inputtype I'm attempting to use (I've tried both an InputObject and a standard Object) <pre><code>var tagsInputType = graphql.NewInputObject(graphql.InputObjectConfig{ Name: "tagsInput", Fields: graphql.Fields{ "keyt": &graphql.Field{ Type: graphql.String, }, "valuet": &graphql.Field{ Type: graphql.String, }, }, }) </code></pre> And here is the graphql query I'm using to test: <pre><code>{ list(location:"blah",rule:"blah") { id,tags(tags:{keyt:"test",valuet:"test"}) { key, value }, { datacentre, handlerData { key, value } } } } </code></pre> I'm getting the following error: <pre><code>wrong result, unexpected errors: [Argument "tags" has invalid value {keyt: "test", valuet: "test"}. In field "keyt": Unknown field. In field "valuet": Unknown field.] </code></pre> The thing is, when I change the type to a string, it works fine. How do I use an object as an input arg? Thanks!

41,230,015

1

0

null

2016-11-01 13:21:11.153 UTC

11

2016-12-19 19:51:55.54 UTC

2016-12-19 18:57:55.893 UTC

null

4,263,818

null

2,851,943

null

1

15

go|graphql

5,832

Had the same issue. Here is what I found from going through the graphql-go source. The <code>Fields</code> of an <code>InputObject</code> have to be of type <code>InputObjectConfigFieldMap</code> or <code>InputObjectConfigFieldMapThunk</code> for the pkg to work. So an <code>InputObject</code> would look like this : <pre><code>var inputType = graphql.NewInputObject( graphql.InputObjectConfig{ Name: "MyInputType", Fields: graphql.InputObjectConfigFieldMap{ "key": &graphql.InputObjectFieldConfig{ Type: graphql.String, }, }, }, ) </code></pre> <hr> Modified the Hello World example to take an <code>Input Object</code> : <pre><code>package main import ( "encoding/json" "fmt" "log" "github.com/graphql-go/graphql" ) func main() { // Schema var inputType = graphql.NewInputObject( graphql.InputObjectConfig{ Name: "MyInputType", Fields: graphql.InputObjectConfigFieldMap{ "key": &graphql.InputObjectFieldConfig{ Type: graphql.String, }, }, }, ) args := graphql.FieldConfigArgument{ "foo": &graphql.ArgumentConfig{ Type: inputType, }, } fields := graphql.Fields{ "hello": &graphql.Field{ Type: graphql.String, Args: args, Resolve: func(p graphql.ResolveParams) (interface{}, error) { fmt.Println(p.Args) return "world", nil }, }, } rootQuery := graphql.ObjectConfig{ Name: "RootQuery", Fields: fields, } schemaConfig := graphql.SchemaConfig{Query: graphql.NewObject(rootQuery)} schema, err := graphql.NewSchema(schemaConfig) if err != nil { log.Fatalf("failed to create new schema, error: %v", err) } // Query query := ` { hello(foo:{key:"blah"}) } ` params := graphql.Params{Schema: schema, RequestString: query} r := graphql.Do(params) if len(r.Errors) > 0 { log.Fatalf("failed to execute graphql operation, errors: %+v", r.Errors) } rJSON, _ := json.Marshal(r) fmt.Printf("%s \n", rJSON) // {“data”:{“hello”:”world”}} } </code></pre>

38,731,271

Clear an input field with Reactjs?

I am using a variable below. <pre><code>var newInput = { title: this.inputTitle.value, entry: this.inputEntry.value }; </code></pre> This is used by my input fields. <pre><code><input type="text" id="inputname" className="form-control" ref={el => this.inputTitle = el} /> <textarea id="inputage" ref={el => this.inputEntry = el} className="form-control" /> <button className="btn btn-info" onClick={this.sendthru}>Add</button> </code></pre> Once I activate <code>{this.sendthru}</code> I want to clear my input fields. However, I am uncertain how to do so. Also, as shown in this example, it was pointed out to me that I should use the <code>ref</code> property for input values. What I am unclear of is what exactly does it mean to have <code>{el => this.inputEntry = el}</code>. What is the significance of <code>el</code> in this situation?

60,087,701

11

0

null

2016-08-02 22:09:24.943 UTC

18

2022-06-27 18:16:06.833 UTC

2019-06-17 09:46:40.373 UTC

null

9,395,140

null

2,934,664

null

1

63

javascript|reactjs

249,308

You can use input type="reset" <pre><code><form action="/action_page.php"> text: <input type="text" name="email" /> <input type="reset" defaultValue="Reset" /> </form> </code></pre>

27,632,217

Warning: Assignment from Incompatible Pointer Type [enabled by default] while assigning Function Address to Function Pointer

I am trying to implement a simple swap function using function pointer but when I assign the function's address to a function pointer: `pointersTofunctionB.c:14:6:warning: assignment from incompatible pointer type [enabled by default]. This is my code: <pre class="lang-c prettyprint-override"><code>#include <stdio.h> void intSwap(int *a,int *b); void charSwap(char *a,char *b); void (*swap)(void*,void*); int main(int argc, char const *argv[]) { int a=20,b=15; char c='j',d='H'; swap=&intSwap;// warning here swap(&a,&b); printf("%d %d\n",a,b); swap=&charSwap;// warning here also swap(&c,&d); printf("%c %c\n",c,d ); return 0; } void intSwap(int *a,int *b) { *a=*a+*b; *b=*a-*b; *a=*a-*b; } void charSwap(char *a,char *b) { char temp; temp=*a; *a=*b; *b=temp; } </code></pre> How can I solve this warning?

27,632,640

4

0

null

2014-12-24 05:58:58.567 UTC

null

2020-03-24 13:12:29.337 UTC

null

3,118,401

null

2,833,303

null

1

6

c|function|pointers|function-pointers

52,244

The warnings appear due to the following quote from the C Standard 6.3.2.3 Pointers <blockquote> 8 A pointer to a function of one type may be converted to a pointer to a function of another type and back again; the result shall compare equal to the original pointer. If a converted pointer is used to call a function whose type is not compatible with the referenced type, the behavior is undefined. </blockquote> That two functions would be compatible their parameters shall have compatible types 6.7.6.3 Function declarators (including prototypes) <blockquote> 15 For two function types to be compatible, both shall specify compatible return types.146) Moreover, the parameter type lists, if both are present, shall agree in the number of parameters and in use of the ellipsis terminator; corresponding parameters shall have compatible types. </blockquote> In your functions parameters are declared as pointers. So that they (pointers) would be compatible they shall be pointers to compatible types 6.7.6.1 Pointer declarators 2 For two pointer types to be compatible, both shall be identically qualified and both shall be pointers to compatible types. However types int or char on the one hand and type void on the other hand are not compatible types. You could define your functions the following way <pre><code>void intSwap( void *a, void *b ) { int *x = a; int *y = b; *x = *x + *y; *y = *x - *y; *x = *x - *y; } void charSwap( void *a, void *b ) { char *c1 = a; char *c2 = b; char temp = *c1; *c1 = *c2; *c2 = temp; } </code></pre>

54,232,530

Merge values in map kotlin

I need merge maps <code>mapA</code> and<code>mapB</code> with pairs of "name" - "phone number" into the final map, sticking together the values for duplicate keys, separated by commas. Duplicate values should be added only once. I need the most idiomatic and correct in terms of language approach. For example: <pre><code>val mapA = mapOf("Emergency" to "112", "Fire department" to "101", "Police" to "102") val mapB = mapOf("Emergency" to "911", "Police" to "102") </code></pre> The final result should look like this: <pre><code>{"Emergency" to "112, 911", "Fire department" to "101", "Police" to "102"} </code></pre> This is my function: <pre><code>fun mergePhoneBooks(mapA: Map<String, String>, mapB: Map<String, String>): Map<String, String> { val unionList: MutableMap <String, String> = mapA.toMutableMap() unionList.forEach { (key, value) -> TODO() } // here's I can't come on with a beatiful solution return unionList } </code></pre>

54,232,917

13

0

null

2019-01-17 09:16:52.543 UTC

7

2022-08-15 15:09:29.157 UTC

null

10,907,345

null

1

25

java|kotlin

38,856

How about: <pre><code>val unionList = (mapA.asSequence() + mapB.asSequence()) .distinct() .groupBy({ it.key }, { it.value }) .mapValues { (_, values) -> values.joinToString(",") } </code></pre> Result: <pre><code>{Emergency=112,911, Fire department=101, Police=102} </code></pre> This will: <ul> <li>produce a lazy <code>Sequence</code> of both maps' key-value pairs</li> <li>group them by key (result: <code>Map<String, List<String></code>)</li> <li>map their values to comma-joined strings (result: <code>Map<String, String></code>)</li> </ul>

29,949,757

Creating Pandas Dataframe between two Numpy arrays, then draw scatter plot

I'm relatively new with numpy and pandas (I'm an experimental physicist so I've been using ROOT for years...). A common plot in ROOT is a 2D scatter plot where, given a list of x- and y- values, makes a "heatmap" type scatter plot of one variable versus the other. How is this best accomplished with numpy and Pandas? I'm trying to use the <code>Dataframe.plot()</code> function, but I'm struggling to even create the Dataframe. <pre><code>import numpy as np import pandas as pd x = np.random.randn(1,5) y = np.sin(x) df = pd.DataFrame(d) </code></pre> First off, this dataframe has shape (1,2), but I would like it to have shape (5,2). If I can get the dataframe the right shape, I'm sure I can figure out the <code>DataFrame.plot()</code> function to draw what I want.

29,951,109

3

0

null

2015-04-29 16:43:29.47 UTC

10

2017-07-25 14:15:19.277 UTC

2015-04-29 18:50:16.98 UTC

null

4,230,591

null

3,886,071

null

1

48

python|numpy|pandas|scatter

127,559

There are a number of ways to create DataFrames. Given 1-dimensional column vectors, you can create a DataFrame by passing it a dict whose keys are column names and whose values are the 1-dimensional column vectors: <pre><code>import numpy as np import pandas as pd x = np.random.randn(5) y = np.sin(x) df = pd.DataFrame({'x':x, 'y':y}) df.plot('x', 'y', kind='scatter') </code></pre>

34,599,888

Google Cloud Platform: How do I rename a Google Cloud Platform project?

Is it possible to rename a Google Cloud Platform project? If so, how? I don't need to change the project ID or number. But I do want to change the project name (the name used by/for humans to identify a cloud platform project). Thanks for any tips!

34,601,514

6

0

null

2016-01-04 21:09:56 UTC

9

2022-02-26 20:59:16.457 UTC

2020-09-01 14:28:13.35 UTC

null

10,907,864

null

123,471

null

1

102

google-cloud-platform

35,608

<ol> <li>Use the hamburger menu in the top left to switch to the "IAM & Admin" section</li> <li>Click Settings</li> <li>Type the new name</li> <li>Press Save</li> <li>Reload the page</li> </ol> For those wondering how to change the project ID, <a href="https://support.google.com/googleapi/answer/7014113?hl=en" rel="nofollow noreferrer">the official documentation says</a>: <blockquote> A project ID cannot be changed after the project is created, so if you are creating a new project, be sure to choose an ID that you'll be comfortable using for the lifetime of the project. </blockquote>

45,981,964

How to get a random element from a list with stream api?

What is the most effective way to get a random element from a list with Java8 stream api? <pre><code>Arrays.asList(new Obj1(), new Obj2(), new Obj3()); </code></pre> Thanks.

45,982,130

9

0

null

2017-08-31 12:54:35.983 UTC

4

2022-09-13 15:13:28.427 UTC

2017-08-31 13:18:09.1 UTC

null

7,294,647

null

1,348,364

null

1

28

java|java-8

30,244

Why with streams? You just have to get a random number from 0 to the size of the list and then call <code>get</code> on this index: <pre><code>Random r = new Random(); ElementType e = list.get(r.nextInt(list.size())); </code></pre> Stream will give you nothing interesting here, but you can try with: <pre><code>Random r = new Random(); ElementType e = list.stream().skip(r.nextInt(list.size())).findFirst().get(); </code></pre> Idea is to skip an arbitrary number of elements (but not the last one!), then get the first element if it exists. As a result you will have an <code>Optional<ElementType></code> which will be non empty and then extract its value with <code>get</code>. You have a lot of options here after having skip. Using streams here is highly inefficient... Note: that none of these solutions take in account empty lists, but the problem is defined on non-empty lists.

31,920,286

Effectively debugging Shiny apps

I have a complex Shiny app spread across multiple files that uses code from several packages. The app works when run locally in R Studio, but on my server it throws a generic error: <blockquote> Error: do not know how to convert 'x' to class "Date" </blockquote> This is probably a simple programming mistake, but figuring out exactly where that mistake is in the code is proving difficult. How can I hunt down and fix the source of errors in Shiny apps? And what tools are available to do this in a systematic way? <hr> There has been some discussion of similar problems on <a href="https://groups.google.com/forum/#!topic/shiny-discuss/M4yy0pZMx_s" rel="noreferrer">Google Groups</a>.

31,945,359

4

0

null

2015-08-10 13:00:37.217 UTC

24

2021-12-22 10:25:50.607 UTC

2018-01-11 12:51:24.59 UTC

null

1,256,041

null

1,256,041

null

1

44

r|debugging|shiny

19,201

You can achieve logging on the server using a combination of <code>logging</code> and <code>shinyjs</code>. <pre><code>install.packages("logging") install.packages("shinyjs") </code></pre> In your ui.R, bind <code>shinyjs</code> using <code>shinyjs::useShinyjs</code>: <pre><code>library(shinyjs) shinyUI( fluidPage( useShinyjs(), # etc... </code></pre> In your server.R, add <code>logjs</code> to the list of log handlers: <pre><code>library(magrittr) library(shinyjs) library(logging) basicConfig() options(shiny.error = function() { logging::logerror(sys.calls() %>% as.character %>% paste(collapse = ", ")) }) shinyServer(function(input, output, session) { printLogJs <- function(x, ...) { logjs(x) T } addHandler(printLogJs) # etc... </code></pre> Then to print something, use <code>loginfo</code>. Other Tips <ol> <li>When running your app locally, such as from RStudio, use <code>options(shiny.error = browser)</code> or <code>options(shiny.error = recover)</code> to identify the source of errors. </li> <li>Put as much business logic into packages and external scripts as possible. Unit-test these whenever you suspect they are causing issues. The <code>testthat</code> package can help here. </li> <li>If you expect a variable to meet certain constraints, add an assertion. For example, if <code>x</code> should be a <code>zoo</code>, put <code>assert_that(is.zoo(x))</code> near the top of your reactive. </li> <li>Beware of the default <code>drop</code> behaviour. Get into the habit of specifying <code>drop = F</code> whenever you want your result to be a <code>data.frame</code>. </li> <li>Try to minimize the number of variables (options, environment, caching, UI state, etc.) that a unit of code depends on. Weakly typed languages are hard enough to debug already! </li> <li>Use proper S4 and S3 classes instead of raw R structures where possible. </li> <li><code>dput</code> will allow you to examine the internal structure of objects, and is very useful when trying to reproduce errors outside of an app. </li> <li>Try to do your debugging in an interactive console, not using <code>print</code> inside an app. This will allow you to iterate more quickly. When debugging outside of an app is not possible, try putting a <code>browser()</code> call just before the problem code. </li> <li>Never use <code>sapply</code> in non-interactive code. With an empty output, it will be unable to infer the type that you want and return an empty <code>list</code>. If your result should be a <code>vector</code>, use <code>vapply</code>. If your result should be a <code>list</code>, use <code>lapply</code>. </li> </ol> You should also look at <a href="https://shiny.rstudio.com/articles/debugging.html" rel="noreferrer">Debugging Shiny Applications</a> from the RStudio team.

2,888,621

autofac's Func<T> to resolve named service

Given registered services: <pre><code>builder.RegisterType<Foo1>().Named<IFoo>("one").As<IFoo>(); builder.RegisterType<Foo2>().Named<IFoo>("two").As<IFoo>(); builder.RegisterType<Foo3>().Named<IFoo>("three").As<IFoo>(); </code></pre> Can I retrieve named implementations of <code>IFoo</code> interface by injecting something like <code>Func<string, IFoo></code> ? <pre><code>public class SomeClass(Func<string, IFoo> foo) { var f = foo("one"); Debug.Assert(f is Foo1); var g = foo("two"); Debug.Assert(g is Foo2); var h = foo("three"); Debug.Assert(h is Foo3); } </code></pre> I know I can do it with <code>Meta<></code>, but I don't want to use it.

2,888,939

1

0

null

2010-05-22 15:17:47.077 UTC

9

2016-08-05 23:26:46.87 UTC

2014-09-19 14:23:36.03 UTC

null

542,190

null

71,965

null

1

15

c#|.net|dependency-injection|ioc-container|autofac

8,075

You could register your own resolving delegate like this: <pre><code>builder.Register<Func<string, IFoo>>(c => { var cc = c.Resolve<IComponentContext>(); return named => cc.ResolveNamed<IFoo>(named); }); </code></pre>

2,931,953

Getting rid of the gradient at the top of an Activity (Android)

How can I get rid of the gradient at the top of my screen (the very top of the blue in the screenshot below... below the notification bar)? <a href="http://dl.dropbox.com/u/299320/device.png">simple screenshot http://dl.dropbox.com/u/299320/device.png</a>

2,932,177

1

null

2010-05-28 19:36:49.053 UTC

15

2011-08-13 20:12:26.863 UTC

2010-05-28 20:01:33.83 UTC

null

76,835

null

76,835

null

1

22

android|user-interface

7,008

This is themable; look at the <code>windowContentOverlay</code> attribute. In particular, you can create a new <a href="http://developer.android.com/guide/topics/ui/themes.html" rel="noreferrer">theme</a>: <pre><code><style name="Theme.Foo" parent="android:style/Theme.Light"> <item name="android:windowContentOverlay">@null</item> </style> </code></pre> And then declare that your activity should use this theme: <pre><code><activity android:name=".FooActivity" android:theme="@style/Theme.Foo"> ... </code></pre> Although a better option is to set this theme for all activities in the application, for consistency: <pre><code><application android:theme="@style/Theme.Foo"> ... </code></pre>

34,316,047

Difference between 'image' and 'build' within docker compose

Please help me understand the difference between 'image' and 'build' within docker compose

34,316,224

2

0

null

2015-12-16 15:35:54.707 UTC

11

2019-08-15 03:34:45.743 UTC

null

5,632,400

null

1

61

docker|dockerfile|docker-compose|docker-registry

19,778

<ul> <li><a href="https://docs.docker.com/compose/compose-file/#image" rel="noreferrer"><code>image</code></a> means <code>docker compose</code> will run a container based on that image</li> <li><a href="https://docs.docker.com/compose/compose-file/#build" rel="noreferrer">build</a> means <code>docker compose</code> will first build an image based on the Dockerfile found in the path associated with build (and then run a container based on that image).</li> </ul> <a href="https://github.com/docker/compose/pull/2458" rel="noreferrer">PR 2458</a> was eventually merged to allow both (and use <code>image</code> as the image name when building, if it exists). <a href="https://stackoverflow.com/users/227926/therobyouknow"><code>therobyouknow</code></a> mentions <a href="https://stackoverflow.com/questions/34316047/difference-between-image-and-build-within-docker-compose/34316224#comment88754834_34316224">in the comments</a>: <blockquote> <code>dockerfile:</code> as a sub-statement beneath <code>build:</code> can be used to specify the filename/path of the Dockerfile. </blockquote> <pre><code>version: '3' services: webapp: build: context: ./dir dockerfile: Dockerfile-alternate args: buildno: 1 </code></pre>

21,335,832

Laravel whereHas on multiple relationships

Does anyone know if this <a href="http://laravel.com/docs/eloquent#querying-relations" rel="noreferrer">new feature</a> can be performed on multiple relationships? For example, I have a query where I want to filter on not only the club name (<a href="https://stackoverflow.com/questions/21116742/wherehas-orwherehas-not-constraining-the-query-as-expected">related question</a>) but also the territory name. In this example, I'd like query results where the club (club relationship) name is Arsenal and the the region is Australia (territory relationship) <pre><code>$ret->with('territory')->with('homeClub')->with('awayClub'); $ret->whereHas('territory',function( $query ){ $query->where('region','Australia'); })->whereHas('homeClub', function ( $query ) { $query->where('name', 'Arsenal' ); })->orWhereHas('awayClub', function ( $query ) { $query->where('name', 'Arsenal' ); }); </code></pre> When executing this query - the result isn't constraining the territory <code>whereHas</code> just the clubs one. Can whereHas be chained to filter the results on previous relationship's whereHas? Any suggestions if not? thanks jon

21,356,760

4

0

null

2014-01-24 15:01:41.07 UTC

8

2022-02-08 11:24:34.603 UTC

2017-05-23 11:33:14.057 UTC

null

-1

null

1,194,469

null

1

19

laravel-4

35,843

Yes that's possible. The generated SQL will probably be: <pre><code>SELECT * FROM ... WHERE (territory constraint) AND (homeClub constratint) OR (awayClub constraint) </code></pre> This means that if <code>awayClub constraint</code> is satisfied, the line will be retrieved. I think you want to add a parenthesis to the generated sql: <pre><code>SELECT * FROM ... WHERE (territory constraint) AND ((homeClub constratint) OR (awayClub constraint)) </code></pre> to do that, you need to nest both queries inside a where: <pre><code>$ret->with('territory')->with('homeClub')->with('awayClub'); $ret->whereHas('territory',function( $query ){ $query->where('region','Australia'); }) ->where(function($subQuery) { $subQuery->whereHas('homeClub', function ( $query ) { $query->where('name', 'Arsenal' ); }) ->orWhereHas('awayClub', function ( $query ) { $query->where('name', 'Arsenal' ); }); }); </code></pre>

35,518,759

How to wait for N seconds between statements in Scala?

I have two statements like this: <pre><code>val a = 1 val b = 2 </code></pre> In between the 2 statements, I want to pause for N seconds like I can in <code>bash</code> with <code>sleep</code> command.

35,519,226

2

0

null

2016-02-20 03:27:35.477 UTC

1

2017-06-26 14:18:22.837 UTC

null

470,341

null

5,691,932

null

1

55

scala|sleep

83,980

You can try: <pre><code>val a = 1 Thread.sleep(1000) // wait for 1000 millisecond val b = 2 </code></pre> You can change 1000 to other values to accommodate to your needs.

51,384,175

Sqlite in flutter, how database assets work

I am looking at this (<a href="https://github.com/tekartik/sqflite/blob/master/doc/opening_asset_db.md" rel="nofollow noreferrer">https://github.com/tekartik/sqflite/blob/master/doc/opening_asset_db.md</a>) for populating data that is already formatted and need for the app, for read functionality only. So my understanding of creating an SQLite database when we already have all the information in an outside CSV file is to, create the class models in a .dart file in my app, such as <pre><code>class User { int id; String _firstName; String _lastName; String _dob; User(this._firstName, this._lastName, this._dob); User.map(dynamic obj) { this._firstName = obj["firstname"]; this._lastName = obj["lastname"]; this._dob = obj["dob"]; } String get firstName => _firstName; String get lastName => _lastName; String get dob => _dob; Map<String, dynamic> toMap() { var map = new Map<String, dynamic>(); map["firstname"] = _firstName; map["lastname"] = _lastName; map["dob"] = _dob; return map; } void setUserId(int id) { this.id = id; } } </code></pre> then if I have a CSV file with all the user information inside of it (with values that correspond to the user class), could I be using the database asset to have that fill out the information and then call to it inside of the flutter app? I realize there are probably many ways to go about this, but What exactly is the .db file storing, and how is it formatted? Can i implement a .csv file into this .db file?

51,387,985

4

0

null

2018-07-17 14:38:41.463 UTC

11

2022-01-05 10:36:50.003 UTC

2020-12-11 04:16:14.19 UTC

user10563627

null

9,989,514

null

1

11

database|sqlite|flutter|dart|sqflite

20,244

First off, you will need to construct a sqlite database from your csv. This can be done in the following way: <ol> <li>Create the necessary table (users.sql) <pre><code>CREATE TABLE users( firstname TEXT NOT NULL, lastname TEXT NOT NULL, dob TEXT NOT NULL ); </code></pre></li> <li>Create the sqlite database <pre><code>sqlite3 database.db < users.sql </code></pre></li> <li>Insert the csv data <pre><code>sqlite3 database.db .mode csv .import data.csv users </code></pre></li> <li>Put database.db into your assets and add that in pubspec.yaml. <pre><code>flutter: # ... assets: - assets/database.db </code></pre></li> <li>In your app, you'll have to copy the asset file into "documents". This is slightly complicated. <pre><code>// Construct a file path to copy database to Directory documentsDirectory = await getApplicationDocumentsDirectory(); String path = join(documentsDirectory.path, "asset_database.db"); // Only copy if the database doesn't exist if (FileSystemEntity.typeSync(path) == FileSystemEntityType.notFound){ // Load database from asset and copy ByteData data = await rootBundle.load(join('assets', 'database.db')); List<int> bytes = data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes); // Save copied asset to documents await new File(path).writeAsBytes(bytes); } </code></pre></li> <li>Lastly, you can access the database like so. <pre><code>Directory appDocDir = await getApplicationDocumentsDirectory(); String databasePath = join(appDocDir.path, 'asset_database.db'); this.db = await openDatabase(databasePath); initialized = true; </code></pre></li> <li>Example query (this._initialize() is step 6) <pre><code>Future<List<Page>> search(String word, int parentId) async { if (!initialized) await this._initialize(); String query = ''' SELECT * FROM users LIMIT 25'''; return await this.db.rawQuery(query); } </code></pre></li> </ol>

43,159,849

Trick to loop/autorefresh docker ps view like top/htop in bash

Is it possible - and if yes, how - to have a self-refreshing view of current Docker containers printed by "docker ps" alike top/htop utilities?

43,160,290

3

0

null

2017-04-01 17:20:05.597 UTC

5

2017-04-01 23:15:28.087 UTC

null

4,422,958

null

1

46

bash|docker|htop

12,613

Use <code>watch</code>: <pre><code>watch docker ps </code></pre> See <a href="https://linux.die.net/man/1/watch" rel="noreferrer"><code>man watch</code></a>

38,369,855

how to put exact number of decimal places on label ggplot bar chart

How can I specify the exact number of decimal places on <code>ggplot</code> bar chart labels? The data: <pre><code>strefa <- c(1:13) a <- c(3.453782,3.295082,3.137755,3.333333,3.500000,3.351351,3.458824,3.318681,3.694175,3.241379,3.138298,3.309524,3.380000) srednie <- data.frame(strefa,a) </code></pre> The code is: <pre><code>ggplot(srednie, aes(x=factor(strefa), y=a, label=round(a, digits = 2))) + geom_bar(position=position_dodge(), stat="identity", colour="darkgrey", width = 0.5) + theme(legend.position="none",axis.text.x = element_blank(), axis.ticks.x = element_blank(), axis.ticks.y = element_blank()) + geom_text(size = 4, hjust = 1.2) + coord_flip(ylim = c(1,6))+ xlab("") + ylab("") </code></pre> As you can see, on bars entitled 5 and 2 the labels are limited to the 1st decimal place. How to show 2 decimal places even if there is i.e. 3.000000 or 5.999999? In such a cases I would like to show 3.00 and 6.00. I tried to use as a <code>aes</code> parameter <code>label=round(a, digits = 2)</code> but it doesn't work.

38,370,083

1

0

null

2016-07-14 09:00:32.57 UTC

7

2018-12-10 11:43:49.71 UTC

2016-07-14 12:04:07.19 UTC

null

4,411,559

null

6,449,064

null

1

26

r|ggplot2|bar-chart

71,125

You could try the following as it rounds to two digits and prints two digits after the decimal. <pre><code>ggplot(srednie, aes(x=factor(strefa), y=a, label=sprintf("%0.2f", round(a, digits = 2)))) + geom_bar(position=position_dodge(), stat="identity", colour="darkgrey", width = 0.5) + theme(legend.position="none",axis.text.x = element_blank(), axis.ticks.x = element_blank(), axis.ticks.y = element_blank()) + geom_text(size = 4, hjust = 1.2) + coord_flip(ylim = c(1,6))+ xlab("") + ylab("") </code></pre> The only modification was changing your code from <pre><code>round(a, digits = 2) </code></pre> to <pre><code>sprintf("%0.2f", round(a, digits = 2)) </code></pre> <a href="https://i.stack.imgur.com/zr8NK.png" rel="noreferrer"><img src="https://i.stack.imgur.com/zr8NK.png" alt="enter image description here"></a>

3,198,765

How to write Russian characters in file?

In console when I'm trying output Russian characters It gives me ??????????????? Who know why? I tried write to file - in this case the same situation. for example <pre><code>f=open('tets.txt','w') f.write('some russian text') f.close </code></pre> inside file is - ?????????????????????????/ or <pre><code>p="some russian text" print p ????????????? </code></pre> In additional Notepad don't allow me to save file with Russian letters. I give this: <blockquote> This file contains characters in Unicode format which will be lost if you save this file as an ANSI encoded text file. To keep the Unicode information, click Cancel below and then select one of the Unicode options from the Encoding drop down list. Continue? </blockquote> How to adjust my system, so I will don't have this problems.

3,204,861

5

8

null

2010-07-07 20:59:44.31 UTC

2

2016-03-25 19:00:12.717 UTC

null

2,306,173

null

375,373

null

1

11

python|windows|unicode|python-2.x|python-unicode

53,639

Here is a worked-out example, please read the comments: <pre><code>#!/usr/bin/env python2 # -*- coding: utf-8 -*- # The above encoding declaration is required and the file must be saved as UTF-8 from __future__ import with_statement # Not required in Python 2.6 any more import codecs p = u"абвгдежзийкл" # note the 'u' prefix print p # probably won't work on Windows due to a complex issue with codecs.open("tets.txt", "w", "utf-16") as stream: # or utf-8 stream.write(p + u"\n") # Now you should have a file called "tets.txt" that can be opened with Notepad or any other editor </code></pre>

2,523,284

Java string replace and the NUL (NULL, ASCII 0) character?

Testing out someone elses code, I noticed a few JSP pages printing funky non-ASCII characters. Taking a dip into the source I found this tidbit: <pre><code>// remove any periods from first name e.g. Mr. John --> Mr John firstName = firstName.trim().replace('.','\0'); </code></pre> Does replacing a character in a String with a null character even work in Java? I know that <code>'\0'</code> will terminate a C-string. Would this be the culprit to the funky characters?

2,523,618

5

1

null

2010-03-26 12:48:02.527 UTC

8

2012-03-17 20:58:36.59 UTC

user166390

null

229,109

null

1

35

java|string|replace|nul

117,345

<blockquote> Does replacing a character in a String with a null character even work in Java? I know that '\0' will terminate a c-string. </blockquote> That depends on how you define what is working. Does it replace all occurrences of the target character with <code>'\0'</code>? Absolutely! <pre><code>String s = "food".replace('o', '\0'); System.out.println(s.indexOf('\0')); // "1" System.out.println(s.indexOf('d')); // "3" System.out.println(s.length()); // "4" System.out.println(s.hashCode() == 'f'*31*31*31 + 'd'); // "true" </code></pre> Everything seems to work fine to me! <code>indexOf</code> can find it, it counts as part of the length, and its value for hash code calculation is 0; everything is as specified by the JLS/API. It DOESN'T work if you expect replacing a character with the null character would somehow remove that character from the string. Of course it doesn't work like that. A null character is still a character! <pre><code>String s = Character.toString('\0'); System.out.println(s.length()); // "1" assert s.charAt(0) == 0; </code></pre> It also DOESN'T work if you expect the null character to terminate a string. It's evident from the snippets above, but it's also clearly specified in JLS (<a href="http://java.sun.com/docs/books/jls/third_edition/html/arrays.html#10.9" rel="noreferrer">10.9. An Array of Characters is Not a String</a>): <blockquote> In the Java programming language, unlike C, an array of <code>char</code> is not a <code>String</code>, and neither a <code>String</code> nor an array of <code>char</code> is terminated by '\u0000' (the NUL character). </blockquote> <hr> <blockquote> Would this be the culprit to the funky characters? </blockquote> Now we're talking about an entirely different thing, i.e. how the string is rendered on screen. Truth is, even "Hello world!" will look funky if you use dingbats font. A unicode string may look funky in one locale but not the other. Even a properly rendered unicode string containing, say, Chinese characters, may still look funky to someone from, say, Greenland. That said, the null character probably will look funky regardless; usually it's not a character that you want to display. That said, since null character is not the string terminator, Java is more than capable of handling it one way or another. <hr> Now to address what we assume is the intended effect, i.e. remove all period from a string, the simplest solution is to use the <code>replace(CharSequence, CharSequence)</code> overload. <pre><code>System.out.println("A.E.I.O.U".replace(".", "")); // AEIOU </code></pre> The <code>replaceAll</code> solution is mentioned here too, but that works with regular expression, which is why you need to escape the dot meta character, and is likely to be slower.

3,109,473

Moving default AVD configuration folder (.android)

After installation of Android SDK, the folder <code>.android</code> was created on the <code>E:\</code> drive. As far as I know, this is the default folder of Android Virtual Devices for configuration files. How can I move <code>.android</code> folder to a different location? (eg. from <code>E:\.android</code> to <code>E:\Android\.android</code>)

3,110,562

8

1

null

2010-06-24 11:24:51.203 UTC

32

2022-08-03 06:08:06.723 UTC

null

361,832

null

361,832

null

1

118

windows|android|android-emulator|avd

94,706

I've found the answer. <ul> <li>Move <code>.android</code> folder to <code>E:\Android</code></li> <li>Create environment variable called ANDROID_SDK_HOME and set its value to <code>E:\Android</code></li> </ul> Setting the environment variable on Windows XP or Windows 7: <ol> <li>Right-click on My Computer and choose "Properties"</li> <li>Click the "Advanced" tab</li> <li>Click the button "Environment Variables".</li> <li>Add New variable</li> </ol>

2,838,490

A table name as a variable

I am trying to execute this query: <pre><code>declare @tablename varchar(50) set @tablename = 'test' select * from @tablename </code></pre> This produces the following error: <blockquote> Msg 1087, Level 16, State 1, Line 5 Must declare the table variable "@tablename". </blockquote> What's the right way to have the table name populated dynamically?

2,838,507

10

0

null

2010-05-15 01:07:17.497 UTC

58

2022-05-20 13:10:28.8 UTC

2021-01-20 07:46:57.14 UTC

null

63,550

null

168,882

null

1

211

sql|sql-server|tsql|variable-names|tablename

516,354

For static queries, like the one in your question, table names and column names need to be static. For dynamic queries, you should generate the full SQL dynamically, and use sp_executesql to execute it. Here is an example of a script used to compare data between the same tables of different databases: Static query: <pre><code>SELECT * FROM [DB_ONE].[dbo].[ACTY] EXCEPT SELECT * FROM [DB_TWO].[dbo].[ACTY] </code></pre> Since I want to easily change the name of <code>table</code> and <code>schema</code>, I have created this dynamic query: <pre><code>declare @schema sysname; declare @table sysname; declare @query nvarchar(max); set @schema = 'dbo' set @table = 'ACTY' set @query = ' SELECT * FROM [DB_ONE].' + QUOTENAME(@schema) + '.' + QUOTENAME(@table) + ' EXCEPT SELECT * FROM [DB_TWO].' + QUOTENAME(@schema) + '.' + QUOTENAME(@table); EXEC sp_executesql @query </code></pre> Since dynamic queries have many details that need to be considered and they are hard to maintain, I recommend that you read: <a href="http://www.sommarskog.se/dynamic_sql.html" rel="noreferrer">The curse and blessings of dynamic SQL</a>

2,939,820

How can I enable cURL for an installed Ubuntu LAMP stack?

I have installed the Ubuntu LAMP stack. But cURL is not enabled, and neither can I can find the extension listed in the INI file. I added it manually, but it didn't work either. How should I enable cURL then?

2,939,827

10

3

null

2010-05-30 18:33:48.157 UTC

50

2022-04-03 01:25:25.333 UTC

2021-02-13 02:03:36.227 UTC

null

63,550

null

349,297

null

1

223

php|ubuntu|curl|lamp

305,955

From <a href="http://buzznol.blogspot.com/2008/12/install-curl-extension-for-php-in.html" rel="noreferrer">Install Curl Extension for PHP in Ubuntu</a>: <pre><code>sudo apt-get install php5-curl </code></pre> After installing libcurl, you should restart the web server with one of the following commands, <pre><code>sudo /etc/init.d/apache2 restart </code></pre> or <pre><code>sudo service apache2 restart </code></pre>

2,806,420

Visual Studio Formatting -- Change Method Color

The default appearance of a method for example, ".ToString()" is by default the color black. I want to make it a different color to stand out but I do not see any options that reference this option specifically. I remember one of former collegues showing me his VS IDE years ago and he had it setup this way but I cannot recall what he did. Does anyone have any ideas on how to do this?

2,806,975

11

0

null

2010-05-10 20:59:18.077 UTC

3

2020-05-25 07:29:51.973 UTC

2010-05-10 21:12:24.067 UTC

user319799

null

337,684

null

1

23

visual-studio|formatting|methods|colors

42,197

The built-in syntax highlighters use lexical analysis. A lexer can classify identifiers, comments, literals, numbers, keywords. The parts you find back in the Tools > Options > Environment > Fonts and Colors dialog. Recognizing that an identifier is a method, property, field requires parsing. Parsing generally only works well when you've got a well-formed program, you rarely have one while you are typing code. So wasn't favored by Microsoft. You can find alternatives in the <a href="https://marketplace.visualstudio.com/search?term=syntax%20highlighting&target=VS&sortBy=Relevance" rel="noreferrer">Visual Studio gallery</a>.

3,110,154

Why is the explicit management of threads a bad thing?

In <a href="https://stackoverflow.com/questions/3109647/which-c-assembly-contains-invoke">a previous question</a>, I made a bit of a faux pas. You see, I'd been reading about threads and had got the impression that they were the tastiest things since kiwi jello. Imagine my confusion then, when I read stuff like this: <blockquote> [T]hreads are A Very Bad Thing. Or, at least, explicit management of threads is a bad thing </blockquote> and <blockquote> Updating the UI across threads is usually a sign that you are abusing threads. </blockquote> Since I kill a puppy every time something confuses me, consider this your chance get your karma back in the black... How should I be using thread?

3,111,104

12

11

null

2010-06-24 13:04:49.883 UTC

32

2010-10-03 17:19:00.463 UTC

2017-05-23 12:08:53.243 UTC

null

-1

null

50,151

null

1

47

c#|multithreading

5,013

Enthusiam for learning about threading is great; don't get me wrong. Enthusiasm for using lots of threads, by contrast, is symptomatic of what I call Thread Happiness Disease. Developers who have just learned about the power of threads start asking questions like "how many threads can I possible create in one program?" This is rather like an English major asking "how many words can I use in a sentence?" Typical advice for writers is to keep your sentences short and to the point, rather than trying to cram as many words and ideas into one sentence as possible. Threads are the same way; the right question is not "how many can I get away with creating?" but rather "how can I write this program so that the number of threads is the minimum necessary to get the job done?" Threads solve a lot of problems, it's true, but they also introduce huge problems: <ul> <li>Performance analysis of multi-threaded programs is often extremely difficult and deeply counterintuitive. I've seen real-world examples in heavily multi-threaded programs in which making a function faster without slowing down any other function or using more memory makes the total throughput of the system smaller. Why? Because threads are often like streets downtown. Imagine taking every street and magically making it shorter without re-timing the traffic lights. Would traffic jams get better, or worse? Writing faster functions in multi-threaded programs drives the processors towards congestion faster. </li> </ul> What you want is for threads to be like interstate highways: no traffic lights, highly parallel, intersecting at a small number of very well-defined, carefully engineered points. That is very hard to do. Most heavily multi-threaded programs are more like dense urban cores with stoplights everywhere. <ul> <li>Writing your own custom management of threads is insanely difficult to get right. The reason is because when you are writing a regular single-threaded program in a well-designed program, the amount of "global state" you have to reason about is typically small. Ideally you write objects that have well-defined boundaries, and that do not care about the control flow that invokes their members. You want to invoke an object in a loop, or a switch, or whatever, you go right ahead.</li> </ul> Multi-threaded programs with custom thread management require global understanding of everything that a thread is going to do that could possibly affect data that is visible from another thread. You pretty much have to have the entire program in your head, and understand all the possible ways that two threads could be interacting in order to get it right and prevent deadlocks or data corruption. That is a large cost to pay, and highly prone to bugs. <ul> <li>Essentially, threads make your methods lie. Let me give you an example. Suppose you have: if (!queue.IsEmpty) queue.RemoveWorkItem().Execute();</li> </ul> Is that code correct? If it is single threaded, probably. If it is multi-threaded, what is stopping another thread from removing the last remaining item after the call to IsEmpty is executed? Nothing, that's what. This code, which locally looks just fine, is a bomb waiting to go off in a multi-threaded program. Basically that code is actually: <pre><code> if (queue.WasNotEmptyAtSomePointInThePast) ... </code></pre> which obviously is pretty useless. So suppose you decide to fix the problem by locking the queue. Is this right? <pre><code>lock(queue) {if (!queue.IsEmpty) queue.RemoveWorkItem().Execute(); } </code></pre> That's not right either, necessarily. Suppose the execution causes code to run which waits on a resource currently locked by another thread, but that thread is waiting on the lock for queue - what happens? Both threads wait forever. Putting a lock around a hunk of code requires you to know everything that code could possibly do with any shared resource, so that you can work out whether there will be any deadlocks. Again, that is an extremely heavy burden to put on someone writing what ought to be very simple code. (The right thing to do here is probably to extract the work item in the lock and then execute it outside the lock. But... what if the items are in a queue because they have to be executed in a particular order? Now that code is wrong too because other threads can then execute later jobs first.) <ul> <li>It gets worse. The C# language spec guarantees that a single-threaded program will have observable behaviour that is exactly as the program is specified. That is, if you have something like "if (M(ref x)) b = 10;" then you know that the code generated will behave as though x is accessed by M before b is written. Now, the compiler, jitter and CPU are all free to optimize that. If one of them can determine that M is going to be true and if we know that on this thread, the value of b is not read after the call to M, then b can be assigned before x is accessed. All that is guaranteed is that the single-threaded program seems to work like it was written. </li> </ul> Multi-threaded programs do not make that guarantee. If you are examining b and x on a different thread while this one is running then you can see b change before x is accessed, if that optimization is performed. Reads and writes can logically be moved forwards and backwards in time with respect to each other in single threaded programs, and those moves can be observed in multi-threaded programs. This means that in order to write multi-threaded programs where there is a dependency in the logic on things being observed to happen in the same order as the code is actually written, you have to have a detailed understanding of the "memory model" of the language and the runtime. You have to know precisely what guarantees are made about how accesses can move around in time. And you cannot simply test on your x86 box and hope for the best; the x86 chips have pretty conservative optimizations compared to some other chips out there. That's just a brief overview of just a few of the problems you run into when writing your own multithreaded logic. There are plenty more. So, some advice: <ul> <li>Do learn about threading.</li> <li>Do not attempt to write your own thread management in production code.</li> <li>Use higher-level libraries written by experts to solve problems with threads. If you have a bunch of work that needs to be done in the background and want to farm it out to worker threads, use a thread pool rather than writing your own thread creation logic. If you have a problem that is amenable to solution by multiple processors at once, use the Task Parallel Library. If you want to lazily initialize a resource, use the lazy initialization class rather than trying to write lock free code yourself.</li> <li>Avoid shared state.</li> <li>If you can't avoid shared state, share immutable state.</li> <li>If you have to share mutable state, prefer using locks to lock-free techniques.</li> </ul>

2,596,805

How do I make git use the editor of my choice for editing commit messages?

How do I globally configure git to use a particular editor (e.g. <code>vim</code>) for commit messages?

2,596,835

30

3

null

2010-04-08 00:28:46.9 UTC

576

2022-08-27 15:56:50.64 UTC

2022-07-11 06:25:00.4 UTC

null

365,102

null

6,340

null

1

3,110

git|vim|emacs|editor|commit-message

1,218,209

<h4>Setting the default editor for Git</h4> Pick one: <ul> <li>Set <a href="http://git-scm.com/book/en/Customizing-Git-Git-Configuration#Basic-Client-Configuration" rel="noreferrer"><code>core.editor</code></a> in your Git config: <pre><code>git config --global core.editor "vim" </code></pre> </li> <li>Set the <a href="http://git-scm.com/docs/git-var#_variables" rel="noreferrer"><code>GIT_EDITOR</code></a> environment variable: <pre><code>export GIT_EDITOR=vim </code></pre> </li> </ul> <hr /> <h4>Setting the default editor for all programs</h4> Set the standardized <code>VISUAL</code> and <code>EDITOR</code> environment variables*: <pre><code>export VISUAL=vim export EDITOR="$VISUAL" </code></pre> NOTE: Setting both is not necessarily needed, but some programs may not use the more-correct <code>VISUAL</code>. See <a href="https://unix.stackexchange.com/questions/4859/visual-vs-editor-whats-the-difference"><code>VISUAL</code> vs. <code>EDITOR</code></a>. <hr /> <h4>Fixing compatibility issues</h4> Some editors require a <code>--wait</code> flag, or they will open a blank page. For example: <ul> <li>Sublime Text (if <a href="https://stackoverflow.com/questions/25152711/subl-command-not-working-command-not-found/25154529">correctly set up</a>; or use the full path to the executable in place of <code>subl</code>): <pre><code>export VISUAL="subl --wait" </code></pre> </li> <li>VS Code (after adding the <a href="https://stackoverflow.com/questions/29955500/code-not-working-in-command-line-for-visual-studio-code-on-osx-mac">shell command</a>): <pre><code>export VISUAL="code --wait" </code></pre> </li> </ul>

10,825,849

MVC3 Action File Size Limit

I'm implementing a jquery based file upload plugin <a href="http://blueimp.github.com/jQuery-File-Upload/" rel="nofollow noreferrer">http://blueimp.github.com/jQuery-File-Upload/</a>. There is a sample MVC3 app that you can download <a href="https://github.com/maxpavlov/jQuery-File-Upload.MVC3" rel="nofollow noreferrer">https://github.com/maxpavlov/jQuery-File-Upload.MVC3</a>. The author of the sample has a comment in the Home View: <blockquote> @*IN ORDER TO USE MVC ACTIONS AS HANDLERS OF AJAX CALLS, USE THE FORM DECLARATION BELOW. (THE ONE COMMENTED OUT) IT IS NOT ADVISED SINCE WHEN USING MVC CONTROLLER TO HANDLE REQUESTS ONE CAN'T CONTROL THE maxMessageLength OF THE POST REQUEST THIS CASTS THE FUNCTIONALITY OF UPLOADING LARGE FILES USELESS, UNLESS YOU SUCRIFICE THE SECURITY AND ALLOW LARGE POST MESSAGE SIZES SITE-WIDE. IT IS BETTER TO USE HTTP HANDLER TO PROCESS UPLOAD REQUESTS UNTIL MVC FRAMEWORK PROVIDES WAYS TO SET maxMessageLength ON PER ACTION BASIS *@ </blockquote> Is this still the case? I've found out I can set the <code><httpRuntime maxRequestLength="x" /></code> in the web.config, but my understanding is that this is a security vulnerability. Is the case also? I would prefer to handle my upload in the controller instead of using an HttpHandler but don't want to be limited by file size and don't want to introduce any security vulnerabilities if I don't have to. Update: According to this post <a href="https://stackoverflow.com/questions/5193842/file-upload-asp-net-mvc3-0">File Upload ASP.NET MVC 3.0</a> the default file size limit is 4mb. I've confirmed this limit <a href="http://msdn.microsoft.com/en-us/library/e1f13641.aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/e1f13641.aspx</a> and understand the vulnerability. Is this the only way to upload a file thru a controller action beyond 4mb?

10,834,379

1

0

null

2012-05-30 23:59:08.9 UTC

10

2014-07-11 07:51:53.333 UTC

2017-05-23 12:25:34.227 UTC

null

-1

null

718,073

null

1

26

asp.net-mvc-3

15,923

You could set upload size limit in web.config for concrete controller action using <a href="http://msdn.microsoft.com/en-us/library/b6x6shw7(v=vs.100).aspx" rel="noreferrer">location</a> element: <pre class="lang-xml prettyprint-override"><code><configuration> <location path="Home/UploadFiles"> <system.web> <httpRuntime maxRequestLength="40960"/> </system.web> </location> </configuration> </code></pre> Where Home is a controller name and UploadFiles is an action name. Size limit is 40MB here. Still, using Http Handler to process file uploads is not a bad solution if you ask me.

10,548,744

Django lazy QuerySet and pagination

I read <a href="https://docs.djangoproject.com/en/dev/topics/db/queries/#querysets-are-lazy">here</a> that Django querysets are lazy, it won't be evaluated until it is actually printed. I have made a simple pagination using the django's built-in pagination. I didn't realize there were apps already such as "django-pagination", and "django-endless" which does that job for. Anyway I wonder whether the QuerySet is still lazy when I for example do this <pre><code>entries = Entry.objects.filter(...) paginator = Paginator(entries, 10) output = paginator.page(page) return HttpResponse(output) </code></pre> And this part is called every time I want to get whatever page I currently I want to view. I need to know since I don't want unnecessary load to the database.

10,549,382

2

0

null

2012-05-11 09:22:23.883 UTC

16

2015-07-15 11:13:43.86 UTC

null

445,600

null

1

27

django|lazy-loading|django-queryset

23,162

If you want to see where are occurring, import <code>django.db.connection</code> and inspect <code>queries</code> <pre><code>>>> from django.db import connection >>> from django.core.paginator import Paginator >>> queryset = Entry.objects.all() </code></pre> Lets create the paginator, and see if any queries occur: <pre><code>>>> paginator = Paginator(queryset, 10) >>> print connection.queries [] </code></pre> None yet. <pre><code>>>> page = paginator.page(4) >>> page <Page 4 of 788> >>> print connection.queries [{'time': '0.014', 'sql': 'SELECT COUNT(*) FROM `entry`'}] </code></pre> Creating the page has produced one query, to count how many entries are in the queryset. The entries have not been fetched yet. Assign the page's objects to the variable 'objects': <pre><code>>>> objects = page.object_list >>> print connection.queries [{'time': '0.014', 'sql': 'SELECT COUNT(*) FROM `entry`'}] </code></pre> This still hasn't caused the entries to be fetched. Generate the <code>HttpResponse</code> from the object list <pre><code>>>> response = HttpResponse(page.object_list) >>> print connection.queries [{'time': '0.014', 'sql': 'SELECT COUNT(*) FROM `entry`'}, {'time': '0.011', 'sql': 'SELECT `entry`.`id`, <snip> FROM `entry` LIMIT 10 OFFSET 30'}] </code></pre> Finally, the entries have been fetched.

10,487,011

Creating a DateTime object with a specific UTC DateTime in PowerShell

I'm trying to create a <code>DateTime</code> object with a specific UTC timestamp in PowerShell. What's the simplest way to do this? I tried: <pre><code>Get-Date -Format (Get-Culture).DateTimeFormat.UniversalSortableDateTimePattern -Date "1970-01-01 00:00:00Z" </code></pre> but I get this output: <pre><code>1969-12-31 19:00:00Z </code></pre> It's a few hours off. Where's my lapse in understanding?

10,487,050

6

0

null

2012-05-07 18:17:02.89 UTC

7

2018-07-19 15:39:38.383 UTC

null

111,327

null

1

42

datetime|powershell|utc

108,097

The <code>DateTime</code> object itself is being created with the proper UTC time. But when PowerShell prints it out it converts it to my local culture and time zone, thus the difference. Proof: <pre><code>$UtcTime = Get-Date -Date "1970-01-01 00:00:00Z" $UtcTime.ToUniversalTime() </code></pre>

10,843,572

How to create Javascript constants as properties of objects using const keyword?

How come constants cannot be set as properties of objects which are variables themselves? <pre><code>const a = 'constant' // all is well // set constant property of variable object const window.b = 'constant' // throws Exception // OR var App = {}; // want to be able to extend const App.goldenRatio= 1.6180339887 // throws Exception </code></pre> And how come constants passed by reference suddenly become variable? EDIT: I know App won't (or rather... SHOULDN'T) be mutable; this is just an observation... <pre><code>(function() { const App; // bunch of code window.com_namespace = App; }()); window.com_namespace; // App window.com_namespace = 'something else'; window.com_namespace; // 'something else' </code></pre> How can a nicely organized, extensible, object-oriented, singly namespaced library containing constants be made with these limitations? EDIT: I believe zi42, but I just have to ask <a href="https://stackoverflow.com/questions/10843809/why-is-it-impossible-to-assign-constant-properties-of-javascript-objects-using-t">why</a>

10,843,598

6

0

null

2012-06-01 02:09:44.403 UTC

14

2022-08-19 22:34:32.69 UTC

2017-05-23 12:18:03.733 UTC

null

-1

null

712,558

null

1

54

javascript|object|properties|constants

61,190

You cannot do it with constants. The only possible way to do something that behaves like you want, but is not using constants, is to define a non-writable property: <pre><code>var obj = {}; Object.defineProperty( obj, "MY_FAKE_CONSTANT", { value: "MY_FAKE_CONSTANT_VALUE", writable: false, enumerable: true, configurable: true }); </code></pre> Regarding your question as to why a <code>const</code> passed to a function becomes variable, the answer is because it's passed by value and not by reference. The function is getting a new variable that has the same value as your constant. edit: thanks to @pst for noting that objects literals in javascript are not actually "passed by reference", but using <a href="https://en.wikipedia.org/wiki/Evaluation_strategy#Call_by_sharing" rel="noreferrer">call-by-sharing</a>: <blockquote> Although this term has widespread usage in the Python community, identical semantics in other languages such as Java and Visual Basic are often described as call-by-value, where the value is implied to be a reference to the object. </blockquote>

5,705,981

How to embed a swf file into html code?

I need to embed a swf file into html code. How can I do it?

5,705,992

3

2

null

2011-04-18 16:32:43.367 UTC

2

2018-02-08 15:26:45.197 UTC

2015-09-08 14:21:53.367 UTC

null

445,131

null

602,202

null

1

html|flash

50,504

Use SWFObject: <a href="http://code.google.com/p/swfobject/wiki/documentation" rel="noreferrer">http://code.google.com/p/swfobject/wiki/documentation</a> <pre><code><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"> <head> <title>SWFObject dynamic embed - step 3</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <script type="text/javascript" src="swfobject.js"></script> <script type="text/javascript"> swfobject.embedSWF("myContent.swf", "myContent", "300", "120", "9.0.0"); </script> </head> <body> <div id="myContent"> Alternative content </div> </body> </html> </code></pre>

33,271,928

Move HTML element upwards on hover

I am trying to move an HTML element up about 10px whenever a user hovers their mouse over it. I did some research on w3schools, but I could not find any information that helped me. Most of their animation examples were using keyframes and I'm pretty sure that's not what I need because I'm trying to trigger an animation when somebody hovers over the element. I could be wrong though and that's why I'm posting here. Here's the element I'm trying to move: <pre><code><div id="arrow"> <a href="#"></a> </div> </code></pre> For my CSS: <pre><code>#arrow { padding-top: 310px; color: #5C6B7E; position: relative; /* some kind of animation property here? */ } #arrow:hover { /* new properties once user hovers */ } </code></pre> I'm not sure what I need to add to make the element animate up, the examples on w3schools weren't of much help. If anybody could point me in the right direction I would be extremely appreciative. Thank you Stack Overflow.

33,272,031

3

1

null

2015-10-22 01:21:20.803 UTC

10

2022-07-13 18:28:34.263 UTC

null

18,206,501

user3635683

null

1

35

html|css|css-animations

81,979

You need not use keyframes for this simple animation. Just CSS transition is enough. Set the <code>transition</code> property in the initial state style rules with the duration. Edit: I just noticed that there is a flicker at the bottom, it can be removed by setting the styles on the icon and hover on the parent. <div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false"> <div class="snippet-code"> <pre class="snippet-code-css lang-css prettyprint-override"><code>#arrow i { position: relative; top: 0; transition: top ease 0.5s; } #arrow:hover i { top: -10px; }</code></pre> <pre class="snippet-code-html lang-html prettyprint-override"><code><link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/css/font-awesome.min.css" rel="stylesheet" /> <div id="arrow"> <a href="#"></a> </div></code></pre> </div> </div>

40,958,613

How to copy URL on button click?

I am trying to copy the current page URL in the text area on button click. Somehow I have tried but is not working. <a href="http://www.w3schools.com/code/tryit.asp?filename=FAF25LWITXR5" rel="noreferrer">http://www.w3schools.com/code/tryit.asp?filename=FAF25LWITXR5</a> <pre class="lang-js prettyprint-override"><code> function Copy() { var Url = document.createElement("textarea"); Url.innerHTML = window.location.href; Copied = Url.createTextRange(); Copied.execCommand("Copy"); } </code></pre> <pre class="lang-html prettyprint-override"><code><div> <input type="button" value="Copy Url" onclick="Copy();" /> Paste: <textarea rows="1" cols="30"></textarea> </div> </code></pre>

40,958,674

7

0

null

2016-12-04 12:28:09.84 UTC

8

2022-01-10 20:26:07.37 UTC

2020-06-18 21:51:17.403 UTC

null

2,437,521

null

5,751,745

null

1

13

javascript|php|jquery|html|web

72,446

<div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false"> <div class="snippet-code"> <pre class="snippet-code-html lang-html prettyprint-override"><code><html> <head> <title></title> </head> <script type="text/javascript"> function Copy() { //var Url = document.createElement("textarea"); urlCopied.innerHTML = window.location.href; //Copied = Url.createTextRange(); //Copied.execCommand("Copy"); } </script> <body> <div> <input type="button" value="Copy Url" onclick="Copy();" /> Paste: <textarea id="urlCopied" rows="1" cols="30"></textarea> </div> </body> </html></code></pre> </div> </div>

32,392,937

How Kafka distributes the topic partitions among the brokers

I have 3 Kafka brokers in 3 different VMs, with one additionally running a Zookeeper. I now create a topic with 8 partitions. The Producer pushes messages to these group of brokers on the created "topic". <ul> <li>How does the Kafka distribute a topic and its partitions among the brokers? </li> <li>Does the Kafka redistribute the topic when a new Kafka Broker joins a cluster?</li> <li>Can the topic partition be increased after the topic was created?</li> </ul>

32,405,720

1

0

null

2015-09-04 07:56:40.707 UTC

10

2021-05-24 19:50:59.22 UTC

null

1,353,364

null

1

18

apache-kafka|kafka-consumer-api

5,059

<ul> <li>When you create a new topic, Kafka places the partitions and replicas in a way that the brokers with least number of existing partitions are used first, and replicas for same partition are on different brokers.</li> <li>When you add a new broker, it is used for new partitions (since it has lowest number of existing partitions), but there is no automatic balancing of existing partitions to the new broker. You can use the replica-reassignment tool to move partitions and replicas to the new broker.</li> <li>Yes, you can add partitions to an existing topic.</li> </ul>

17,874,489

Disambiguate overloaded member function pointer being passed as template parameter

I am attempting to recreate the Observer pattern where I can perfectly forward parameters to a given member function of the observers. If I attempt to pass the address of a member function which has multiple overrides, it cannot deduce the correct member function based on the arguments. <pre><code>#include <iostream> #include <vector> #include <algorithm> template<typename Class> struct observer_list { template<typename Ret, typename... Args, typename... UArgs> void call(Ret (Class::*func)(Args...), UArgs&&... args) { for (auto obj : _observers) { (obj->*func)(std::forward<UArgs>(args)...); } } std::vector<Class*> _observers; }; struct foo { void func(const std::string& s) { std::cout << this << ": " << s << std::endl; } void func(const double d) { std::cout << this << ": " << d << std::endl; } }; int main() { observer_list<foo> l; foo f1, f2; l._observers = { &f1, &f2 }; l.call(&foo::func, "hello"); l.call(&foo::func, 0.5); return 0; } </code></pre> This fails to compile with <code>template argument deduction/substitution failed</code>. Note that I had <code>Args...</code> and <code>UArgs...</code> because I need to be able to pass parameters which are not necessarily the same type asthe type of the function signature, but are convertible to said type. I was thinking I could use a <code>std::enable_if<std::is_convertible<Args, UArgs>></code> call to disambiguate, but I don't believe I can do this with a variadic template parameter pack? How can I get the template argument deduction to work here?

17,875,252

1

null

2013-07-26 06:35:18.193 UTC

10

2014-10-24 22:06:38.097 UTC

2013-07-26 07:18:12.977 UTC

null

500,104

null

955,273

null

1

47

c++|templates|c++11|typetraits

19,559

The issue is here: <pre><code>l.call(&foo::func, "hello"); l.call(&foo::func, 0.5); </code></pre> For both lines, the compiler doesn't know which <code>foo::func</code> you are referring to. Hence, you have to disambiguate yourself by providing the type information that is missing (i.e., the type of <code>foo:func</code>) through casts: <pre><code>l.call(static_cast<void (foo::*)(const std::string&)>(&foo::func), "hello"); l.call(static_cast<void (foo::*)(const double )>(&foo::func), 0.5); </code></pre> Alternatively, you can provide the template arguments that the compiler cannot deduce and that define the type of <code>func</code>: <pre><code>l.call<void, const std::string&>(&foo::func, "hello"); l.call<void, double >(&foo::func, 0.5); </code></pre> Notice that you have to use <code>double</code> and not <code>const double</code> above. The reason is that generally <code>double</code> and <code>const double</code> are two different types. However, there's one situation where <code>double</code> and <code>const double</code> are considered as if they were the same type: as function arguments. For instance, <pre><code>void bar(const double); void bar(double); </code></pre> are not two different overloads but are actually the same function.

52,272,533

Does every stateful intermediate Stream API operation guarantee a new source collection?

Is the following statement true? <blockquote> The <code>sorted()</code> operation is a “stateful intermediate operation”, which means that subsequent operations no longer operate on the backing collection, but on an internal state. </blockquote> (<a href="https://www.toptal.com/java/top-10-most-common-java-development-mistakes" rel="nofollow noreferrer">Source</a> and <a href="https://dzone.com/articles/java-8-friday-10-subtle" rel="nofollow noreferrer">source</a> - they seem to copy from each other or come from the same source.) Disclaimer: I am aware the following snippets are not legit usages of Java Stream API. Don't use in the production code. I have tested <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#sorted--" rel="nofollow noreferrer"><code>Stream::sorted</code></a> as a snippet from sources above: <pre><code>final List<Integer> list = IntStream.range(0, 10).boxed().collect(Collectors.toList()); list.stream() .filter(i -> i > 5) .sorted() .forEach(list::remove); System.out.println(list); // Prints [0, 1, 2, 3, 4, 5] </code></pre> It works. I replaced <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#sorted--" rel="nofollow noreferrer"><code>Stream::sorted</code></a> with <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#distinct--" rel="nofollow noreferrer"><code>Stream::distinct</code></a>, <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#limit-long-" rel="nofollow noreferrer"><code>Stream::limit</code></a> and <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#skip-long-" rel="nofollow noreferrer"><code>Stream::skip</code></a>: <pre><code>final List<Integer> list = IntStream.range(0, 10).boxed().collect(Collectors.toList()); list.stream() .filter(i -> i > 5) .distinct() .forEach(list::remove); // Throws NullPointerException </code></pre> To my surprise, the <code>NullPointerException</code> is thrown. All the tested methods follow the <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/package-summary.html#StreamOps" rel="nofollow noreferrer">stateful intermediate operation</a> characteristics. Yet, this unique behavior of <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#sorted--" rel="nofollow noreferrer"><code>Stream::sorted</code></a> is not documented nor the <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/package-summary.html#StreamOps" rel="nofollow noreferrer">Stream operations and pipelines</a> part explains whether the stateful intermediate operations really guarantee a new source collection. Where my confusion comes from and what is the explanation of the behavior above?

52,272,725

3

1

null

2018-09-11 09:11:38.697 UTC

6

2022-01-02 13:36:21.563 UTC

null

3,764,965

null

3,764,965

null

1

33

java|java-8|java-stream

1,821

The API documentation makes no such guarantee “that subsequent operations no longer operate on the backing collection”, hence, you should never rely on such a behavior of a particular implementation. Your example happens to do the desired thing by accident; there’s not even a guarantee that the <code>List</code> created by <code>collect(Collectors.toList())</code> supports the <code>remove</code> operation. To show a counter-example <pre><code>Set<Integer> set = IntStream.range(0, 10).boxed() .collect(Collectors.toCollection(TreeSet::new)); set.stream() .filter(i -> i > 5) .sorted() .forEach(set::remove); </code></pre> throws a <code>ConcurrentModificationException</code>. The reason is that the implementation optimizes this scenario, as the source is already sorted. In principle, it could do the same optimization to your original example, as <code>forEach</code> is explicitly performing the action in no specified order, hence, the sorting is unnecessary. There are other optimizations imaginable, e.g. <code>sorted().findFirst()</code> could get converted to a “find the minimum” operation, without the need to copy the element into a new storage for sorting. So the bottom line is, when relying on unspecified behavior, what may happen to work today, may break tomorrow, when new optimizations are added.

21,065,616

Multiple "could not be resolved" problems using Eclipse with minGW

I have recently installed (the latest builds of) 'Eclipse IDE for C/C++ Developers' and minGW (4.8.1) to help me to get back into C++ after a long time away. I have added <code>-std=c++11</code> to <code>Other flags</code> at <code>C/C++ Build/Settings/Tool Settings/GCC C++ Compiler/Miscellaneous</code> I have a small program utilizing a number of C++11 features (e.g. using the <code>chrono</code> library, <code>.emplace_back</code>). After Run I get multiple unresolved issues in the Problems window, as Pasted below). Interestingly, the program does compile and run ok. <ol> <li>With this, is there something I'm not setting up in Eclipse to resolve these issues?</li> <li>Does anyone know if there still an issue with the <code>to_string()</code> function in minGW (4.8.1) e.g. the following does not compile: <pre><code>window.setTitle("Bullets on screen: " + to_string(bullets.size()) + " currentSlice: " + to_string(currentSlice) + " FT: " + to_string(ft) + " FPS: " + to_string(fps) ); </code></pre> It does compile using Visual Studio Express 2013 (though it has an issue with the accuracy of the <code>chrono</code> library, hence the switch to minGW). Thanks.</li> </ol> Eclipse 'Problem' window output: <pre><code>Description Resource Path Location Type Symbol 'duration' could not be resolved chronotest.cpp /chronotest/src line 19 Semantic Error Function 'now' could not be resolved Test2.cpp /Test2/src line 143 Semantic Error Function 'duration_cast' could not be resolved Test2.cpp /Test2/src line 160 Semantic Error Function 'now' could not be resolved Test2.cpp /Test2/src line 158 Semantic Error Symbol 'chrono' could not be resolved Test2.cpp /Test2/src line 8 Semantic Error Type 'std::centi' could not be resolved chronotest.cpp /chronotest/src line 20 Semantic Error Type 'std::chrono::seconds' could not be resolved chronotest.cpp /chronotest/src line 24 Semantic Error Type 'std::time_t' could not be resolved chronotest.cpp /chronotest/src line 48 Semantic Error Symbol 'duration' could not be resolved chronotest.cpp /chronotest/src line 47 Semantic Error Function 'now' could not be resolved chronotest.cpp /chronotest/src line 44 Semantic Error Function 'now' could not be resolved chronotest.cpp /chronotest/src line 39 Semantic Error Type 'std::chrono::system_clock' could not be resolved chronotest.cpp /chronotest/src line 38 Semantic Error Function 'end' could not be resolved Test2.cpp /Test2/src line 214 Semantic Error Symbol 'time_point' could not be resolved chronotest.cpp /chronotest/src line 38 Semantic Error Function 'end' could not be resolved Test2.cpp /Test2/src line 212 Semantic Error Type 'milli' could not be resolved Test2.cpp /Test2/src line 161 Semantic Error Method 'count' could not be resolved Test2.cpp /Test2/src line 161 Semantic Error Symbol 'duration_cast' could not be resolved Test2.cpp /Test2/src line 160 Semantic Error Symbol 'duration' could not be resolved Test2.cpp /Test2/src line 161 Semantic Error Method 'count' could not be resolved chronotest.cpp /chronotest/src line 51 Semantic Error Symbol 'duration_cast' could not be resolved chronotest.cpp /chronotest/src line 30 Semantic Error Method 'count' could not be resolved chronotest.cpp /chronotest/src line 30 Semantic Error Function 'to_time_t' could not be resolved chronotest.cpp /chronotest/src line 48 Semantic Error Method 'count' could not be resolved chronotest.cpp /chronotest/src line 32 Semantic Error Function 'ctime' could not be resolved chronotest.cpp /chronotest/src line 50 Semantic Error Method 'count' could not be resolved chronotest.cpp /chronotest/src line 33 Semantic Error Symbol 'duration' could not be resolved chronotest.cpp /chronotest/src line 22 Semantic Error Invalid arguments ' Candidates are: __gnu_cxx::__normal_iterator<Bullet *,std::vector<Bullet,std::allocator<Bullet>>> erase(__gnu_cxx::__normal_iterator<Bullet *,std::vector<Bullet,std::allocator<Bullet>>>) __gnu_cxx::__normal_iterator<Bullet *,std::vector<Bullet,std::allocator<Bullet>>> erase(__gnu_cxx::__normal_iterator<Bullet *,std::vector<Bullet,std::allocator<Bullet>>>, __gnu_cxx::__normal_iterator<Bullet *,std::vector<Bullet,std::allocator<Bullet>>>) ' Test2.cpp /Test2/src line 212 Semantic Error Symbol 'ratio' could not be resolved chronotest.cpp /chronotest/src line 22 Semantic Error Invalid arguments ' Candidates are: #0 remove_if(#0, #0, #1) ' Test2.cpp /Test2/src line 212 Semantic Error Symbol 'duration_cast' could not be resolved chronotest.cpp /chronotest/src line 28 Semantic Error Method 'count' could not be resolved chronotest.cpp /chronotest/src line 28 Semantic Error Method 'emplace_back' could not be resolved Test2.cpp /Test2/src line 191 Semantic Error Symbol 'ratio' could not be resolved chronotest.cpp /chronotest/src line 19 Semantic Error Symbol 'duration' could not be resolved chronotest.cpp /chronotest/src line 20 Semantic Error Symbol 'duration' could not be resolved chronotest.cpp /chronotest/src line 21 Semantic Error Function 'begin' could not be resolved Test2.cpp /Test2/src line 212 Semantic Error Symbol 'ratio' could not be resolved chronotest.cpp /chronotest/src line 21 Semantic Error </code></pre> <hr> [Edit]: Apologies for not including error details for the remaining "to_string". The Eclipse 'Problem' window output has the following: <pre><code> Description Resource Path Location Type 'to_string' was not declared in this scope Test2.cpp /Test2/src line 170 C/C++ Problem Function 'to_string' could not be resolved Test2.cpp /Test2/src line 170 Semantic Error Function 'to_string' could not be resolved Test2.cpp /Test2/src line 170 Semantic Error unused variable 'currentSlice' [-Wunused-variable] Test2.cpp /Test2/src line 125 C/C++ Problem Function 'to_string' could not be resolved Test2.cpp /Test2/src line 170 Semantic Error Invalid arguments ' Candidates are: void setTitle(const sf::String &) ' Test2.cpp /Test2/src line 170 Semantic Error Function 'to_string' could not be resolved Test2.cpp /Test2/src line 170 Semantic Error </code></pre>

21,065,897

3

1

null

2014-01-11 17:41:34.743 UTC

6

2018-05-30 11:52:00.743 UTC

2014-01-11 18:37:56.79 UTC

null

2,521,883

null

2,521,883

null

1

20

c++|eclipse|gcc|c++11|mingw32

71,150

Go to <code>Project -> Properties -> C/C++ General -> Preprocessor Include Paths, Macros, etc. -> Providers -> CDT GCC built-in compiler settings</code>, deactivate <code>Use global provider shared between projects</code> and add the command line argument <code>-std=c++11</code>. The eclipse live code analysis does not share the same settings with the build compiler. You can also change the setting globally (not just for the project) in <code>Window -> Preferences -> C/C++ -> Build -> Settings -> CDT GCC Built-in Compiler Settings</code>. Edit: You need to <code>#include <string></code> to use <code>std::to_string</code>.

54,598,322

How to make Typescript infer the keys of an object but define type of its value?

I want to define the type of an object but let typescript infer the keys and don't have as much overhead to make and maintain a UnionType of all keys. Typing an object will allow all strings as keys: <pre><code>const elementsTyped: { [key: string]: { nodes: number, symmetric?: boolean } } = { square: { nodes: 4, symmetric: true }, triangle: { nodes: 3 } } function isSymmetric(elementType: keyof typeof elementsTyped): boolean { return elementsTyped[elementType].symmetric; } isSymmetric('asdf'); // works but shouldn't </code></pre> Inferring the whole object will show an error and allows all kind of values: <pre><code>const elementsInferred = { square: { nodes: 4, symmetric: true }, triangle: { nodes: 3 }, line: { nodes: 2, notSymmetric: false /* don't want that to be possible */ } } function isSymmetric(elementType: keyof typeof elementsInferred): boolean { return elementsInferred[elementType].symmetric; // Property 'symmetric' does not exist on type '{ nodes: number; }'. } </code></pre> The closest I got was this, but it don't want to maintain the set of keys like that: <pre><code>type ElementTypes = 'square' | 'triangle'; // don't want to maintain that :( const elementsTyped: { [key in ElementTypes]: { nodes: number, symmetric?: boolean } } = { square: { nodes: 4, symmetric: true }, triangle: { nodes: 3 }, lines: { nodes: 2, notSymmetric: false } // 'lines' does not exist in type ... // if I add lines to the ElementTypes as expected => 'notSymmetric' does not exist in type { nodes: number, symmetric?: boolean } } function isSymmetric(elementType: keyof typeof elementsTyped): boolean { return elementsTyped[elementType].symmetric; } isSymmetric('asdf'); // Error: Argument of type '"asdf"' is not assignable to parameter of type '"square" | "triangle"'. </code></pre> Is there a better way to define the object without maintaining the set of keys?

54,598,743

1

null

2019-02-08 18:31:38.197 UTC

17

2019-02-08 19:05:43.163 UTC

null

7,557,340

null

1

52

typescript

13,617

So you want something that infers keys but restricts the value types and uses <a href="https://www.typescriptlang.org/docs/handbook/interfaces.html#excess-property-checks" rel="noreferrer">excess property checking</a> to disallow extra properties. I think the easiest way to get that behavior is to introduce a helper function: <pre><code>// Let's give a name to this type interface ElementType { nodes: number, symmetric?: boolean } // helper function which infers keys and restricts values to ElementType const asElementTypes = <T>(et: { [K in keyof T]: ElementType }) => et; </code></pre> This helper function <a href="https://www.typescriptlang.org/docs/handbook/advanced-types.html#inference-from-mapped-types" rel="noreferrer">infers</a> the type <code>T</code> from the mapped type of <code>et</code>. Now you can use it like this: <pre><code>const elementsTyped = asElementTypes({ square: { nodes: 4, symmetric: true }, triangle: { nodes: 3 }, line: { nodes: 2, notSymmetric: false /* error where you want it */} }); </code></pre> The type of the resulting <code>elementsTyped</code> will (once you fix the error) have inferred keys <code>square</code>, <code>triangle</code>, and <code>line</code>, with values <code>ElementType</code>. Hope that works for you. Good luck!

35,620,318

Allocate or Limit resource for pods in Kubernetes?

The resource limit of Pod has been set as: <pre><code>resource limit cpu: 500m memory: 5Gi </code></pre> and there's <code>10G</code> mem left on the node. I've created <code>5</code> pods in a short time successfully, and the node maybe still have some mem left, e.g. <code>8G</code>. The mem usage is growing as the time goes on, and reach the limit (<code>5G x 5 = 25G > 10G</code>), then the node will be out of response. In order to ensure the usability, is there a way to set the resource limit on the node? <h2>Update</h2> The core problem is that pod memory usage does not always equal to the limit, especially in the time when it just starts. So there can be unlimited pods created as soon as possible, then make all nodes full load. That's not good. There might be something to allocate resources rather than setting the limit. <h2>Update 2</h2> I've tested again for the limits and resources: <pre><code>resources: limits: cpu: 500m memory: 5Gi requests: cpu: 500m memory: 5Gi </code></pre> The total mem is 15G and left 14G, but 3 pods are scheduled and running successfully: <pre><code>> free -mh total used free shared buff/cache available Mem: 15G 1.1G 8.3G 3.4M 6.2G 14G Swap: 0B 0B 0B > docker stats CONTAINER CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O 44eaa3e2d68c 0.63% 1.939 GB / 5.369 GB 36.11% 0 B / 0 B 47.84 MB / 0 B 87099000037c 0.58% 2.187 GB / 5.369 GB 40.74% 0 B / 0 B 48.01 MB / 0 B d5954ab37642 0.58% 1.936 GB / 5.369 GB 36.07% 0 B / 0 B 47.81 MB / 0 B </code></pre> It seems that the node will be crushed soon XD <h2>Update 3</h2> Now I change the resources limits, request <code>5G</code> and limit <code>8G</code>: <pre><code>resources: limits: cpu: 500m memory: 5Gi requests: cpu: 500m memory: 8Gi </code></pre> The results are: <a href="https://i.stack.imgur.com/rhpEB.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rhpEB.jpg" alt="enter image description here"></a> According to the <a href="https://github.com/kubernetes/kubernetes/blob/8c60068b368f8ec1cd21fdf25d44c7b165aa9d27/plugin/pkg/scheduler/algorithm/predicates/predicates.go#L393" rel="nofollow noreferrer">k8s source code about the resource check</a>: <a href="https://i.stack.imgur.com/auyM2.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/auyM2.jpg" alt="enter image description here"></a> The total memory is only <code>15G</code>, and all the pods needs <code>24G</code>, so all the pods may be killed. (my single one container will cost more than <code>16G</code> usually if not limited.) It means that you'd better keep the <code>requests</code> exactly equals to the <code>limits</code> in order to avoid pod killed or node crush. As if the <code>requests</code> value is not specified, it will be <a href="http://kubernetes.io/v1.1/docs/user-guide/compute-resources.html" rel="nofollow noreferrer">set to the <code>limit</code> as default</a>, so what exactly <code>requests</code> used for? I think only <code>limits</code> is totally enough, or IMO, on the contrary of what K8s claimed, I rather like to set the resource request greater than the limit, in order to ensure the usability of nodes. <h2>Update 4</h2> Kubernetes <a href="https://github.com/kubernetes/kubernetes/blob/1ef28633870d66fba6883bf1d667dbcfd83f200b/plugin/pkg/scheduler/algorithm/predicates/predicates.go#L120" rel="nofollow noreferrer">1.1 schedule the pods mem requests</a> via the formula: <code>(capacity - memoryRequested) >= podRequest.memory</code> It seems that kubernetes is not caring about memory usage as <a href="https://stackoverflow.com/users/5289649/vishnu-kannan">Vishnu Kannan</a> said. So the node will be crushed if the mem used much by other apps. Fortunately, from the commit <a href="https://github.com/kubernetes/kubernetes/commit/e64fe82245303f08f32b0fb9a2fa9efe4a08f91f" rel="nofollow noreferrer">e64fe822</a>, the formula has been changed as: <code>(allocatable - memoryRequested) >= podRequest.memory</code> waiting for the k8s v1.2!

35,634,337

2

0

null

2016-02-25 06:51:25.877 UTC

9

2020-03-13 06:35:04.343 UTC

null

8,123,139

null

5,658,049

null

1

12

docker|kubernetes|cgroups

7,414

Kubernetes resource specifications have two fields, <code>request</code> and <code>limit</code>. <code>limits</code> place a cap on how much of a resource a container can use. For memory, if a container goes above its limits, it will be OOM killed. For CPU, its usage may be throttled. <code>requests</code> are different in that they ensure the node that the pod is put on has at least that much capacity available for it. If you want to make sure that your pods will be able to grow to a particular size without the node running out of resources, specify a request of that size. This will limit how many pods you can schedule, though -- a 10G node will only be able to fit 2 pods with a 5G memory request.

18,814,806

Can bower automatically write <script> tags into index.html?

I'm using yeoman's backbone generator, and I ran this: <pre><code>bower install backbone.localStorage -S </code></pre> And I manually had to insert this into index.html: <pre><code><script src="bower_components/backbone.localStorage/backbone.localStorage.js"></script> </code></pre> Is there some way for bower to automatically insert <code><script></code> tags? I thought part of the benefit of bower was not having to figure out in which order to include your scripts?

21,320,207

4

0

null

2013-09-15 16:38:29.677 UTC

18

2015-10-24 12:17:09.227 UTC

null

685,125

null

1

62

yeoman|bower

37,016

Just run <pre><code>grunt bowerInstall </code></pre> after bower install

8,886,367

Running Chrome with extension in kiosk mode

I really need to run Chrome in kiosk mode with an extension. If I start chrome with <code>--app-id=xxxx</code> it runs the app, but <code>--kiosk</code> is ignored. If I start it with <code>--kiosk</code> the app-id is ignored. Is there any way to do both? Starting in full screen (F11 mode) is not going to work because of the bubble window at the top and the user can exit.

8,889,306

6

0

null

2012-01-16 21:16:12.843 UTC

2

2017-06-08 19:30:56.877 UTC

2012-01-17 13:05:09.967 UTC

null

1,143,495

null

1,152,692

null

1

10

google-chrome

49,886

Go to options and for "Home Page" pick "Open this page" and enter the url for your web app and then add --kiosk to your command line. To get the url for your app I usually just open the app in a tab, right click and pick view source and then youll get something like view-source:chrome-extension://hiddpjhppcbepfekmomnlopbjjjhilhk/popup.html for its url, copy everything after view-source: and put that as your homepage.

55,497,072

Execute async method on button click in blazor

I created a "Razor Components" project. I am trying to execute an asynchronous method when pressing a button, but could not figure out the syntax yet. This is my Index.razor: <pre><code>@page "/" @inject GenericRepository<Person> PersonRepository @foreach (var person in persons) { <button onclick="@(() => Delete(person.Id))">❌</button> } @functions { async void Delete(Guid personId) { await this.PersonRepository.Delete(personId); } } </code></pre> When I click the button, nothing happens. I tried various return types (e.g. <code>Task</code>) and stuff, but cannot figure out how to make it work. Please let me know if I need to provide more information. Every documentation / tutorial only just works with non-async void calls on button click. Thanks in advance.

55,497,287

2

0

null

2019-04-03 14:03:30.44 UTC

1

2021-11-08 11:03:24.26 UTC

null

1,865,613

null

1,865,613

null

1

36

c#|razor|blazor|blazor-server-side|razor-components

41,469

You need to call the <code>Delete</code> method properly and make it return <code>Task</code> instead of <code>void</code>: <pre><code><button onclick="@(async () => await Delete(person.Id))">❌</button> @functions { // ... async Task Delete(Guid personId) { await this.PersonRepository.Delete(personId); } } </code></pre>

448,204

Creating a custom authentication with Acegi/Spring Security

I'm having trouble discovering exactly what I need to implement in order to use a custom authentication method with my web application using Spring Security. I have a Grails application with the Spring Security plugin that currently uses the standard user/password authentication with a browser form. This is working correctly. I need to implement a mechanism alongside of this that implements a type of <a href="http://en.wikipedia.org/wiki/Message_authentication_code" rel="noreferrer">MAC</a> authentication. If the HTTP request contains several parameters (e.g. a user identifier, timestamp, signature, etc.) I need to take those parameters, perform some hashing and signature/timestamp comparisons, and then authenticate the user. I'm not 100% sure where to start with this. What Spring Security classes do I need to extend/implement? I have read the <a href="http://www.acegisecurity.org/guide/springsecurity.html" rel="noreferrer">Reference Documentation</a> and have an okay understanding of the concepts, but am not really sure if I need a Filter or Provider or Manager, or where/how exactly to create <a href="http://static.springframework.org/spring-security/site/apidocs/org/springframework/security/Authentication.html" rel="noreferrer">Authentication</a> objects. I've messed around trying to extend <a href="http://static.springframework.org/spring-security/site/apidocs/org/springframework/security/ui/AbstractProcessingFilter.html" rel="noreferrer">AbstractProcessingFilter</a> and/or implement <a href="http://static.springframework.org/spring-security/site/apidocs/org/springframework/security/providers/AuthenticationProvider.html" rel="noreferrer">AuthenticationProvider</a>, but I just get caught up understanding how I make them all play nicely.

737,382

3

0

null

2009-01-15 19:51:47.527 UTC

10

2013-03-21 13:57:38.783 UTC

2010-08-17 22:16:17.73 UTC

null

29,995

robhruska

29,995

null

1

21

spring-security

25,060

<ol> <li>Implement a custom <code>AuthenticationProvider</code> which gets all your authentication information from the <code>Authentication</code>: <code>getCredentials()</code>, <code>getDetails()</code>, and <code>getPrincipal()</code>. Tie it into your Spring Security authentication mechanism using the following configuration snippet:</li> </ol> <pre class="lang-xml prettyprint-override"><code><bean id="myAuthenticationProvider" class="com.example.MyAuthenticationProvider"> <security:custom-authentication-provider /> </bean> </code></pre> <ol start="2"> <li>This step is optional, if you can find a suitable one from standard implementations. If not, implement a class extending the <code>Authentication</code> interface on which you can put your authentication parameters: <pre><code>(e.g. a user identifier, timestamp, signature, etc.) </code></pre></li> <li>Extend a custom <code>SpringSecurityFilter</code> which ties the above two classes together. For example, the Filter might get the <code>AuthenticationManager</code> and call <code>authenticate()</code> using your implementation of <code>Authentication</code> as input. You can extend <a href="https://fisheye.springsource.org/browse/~tag=3.0.5.RELEASE/spring-security/web/src/main/java/org/springframework/security/web/authentication/AbstractAuthenticationProcessingFilter.java?r=6ac858814407cee65e3c30779cb271ecaf3abd19" rel="nofollow noreferrer">AbstractAuthenticationProcessingFilter</a> as a start. You can reference <a href="https://fisheye.springsource.org/browse/~tag=3.0.5.RELEASE/spring-security/web/src/main/java/org/springframework/security/web/authentication/UsernamePasswordAuthenticationFilter.java?hb=true" rel="nofollow noreferrer">UsernamePasswordAuthenticationFilter</a> which extends <code>AbstractAuthenticationProcessingFilter</code>. <code>UsernamePasswordAuthenticationFilter</code> implements the standard Username/Password Authentication.</li> <li>Configure your Spring Security to add or replace the standard <code>AUTHENTICATION_PROCESSING_FILTER</code>. For Spring Security Filter orders, see <a href="http://static.springsource.org/spring-security/site/docs/3.0.x/reference/ns-config.html#filter-stack" rel="nofollow noreferrer">http://static.springsource.org/spring-security/site/docs/3.0.x/reference/ns-config.html#filter-stack</a> Here is a configuration snippet for how to replace it with your implementation:</li> </ol> <pre class="lang-xml prettyprint-override"><code><beans:bean id="myFilter" class="com.example.MyAuthenticationFilter"> <custom-filter position="AUTHENTICATION_PROCESSING_FILTER"/> </beans:bean> </code></pre>

203,469

How to use enums in Oracle?

How do you use enums in Oracle using SQL only? (No PSQL) In MySQL you can do: <pre><code>CREATE TABLE sizes ( name ENUM('small', 'medium', 'large') ); </code></pre> What would be a similar way to do this in Oracle?

203,547

3

0

null

2008-10-15 01:48:37.78 UTC

16

2018-08-15 13:34:35.92 UTC

2008-10-15 02:43:58.073 UTC

Robert Gould

15,124

Robert Gould

15,124

null

1

47

database|oracle|enums

80,241

Reading a bit about the <a href="http://dev.mysql.com/doc/refman/5.0/en/enum.html" rel="noreferrer">MySQL enum</a>, I'm guessing the closest equivalent would be a simple check constraint <pre><code>CREATE TABLE sizes ( name VARCHAR2(10) CHECK( name IN ('small','medium','large') ) ); </code></pre> but that doesn't allow you to reference the value by the index. A more complicated foreign key relationship would also be possible <pre><code>CREATE TABLE valid_names ( name_id NUMBER PRIMARY KEY, name_str VARCHAR2(10) ); INSERT INTO valid_sizes VALUES( 1, 'small' ); INSERT INTO valid_sizes VALUES( 2, 'medium' ); INSERT INTO valid_sizes VALUES( 3, 'large' ); CREATE TABLE sizes ( name_id NUMBER REFERENCES valid_names( name_id ) ); CREATE VIEW vw_sizes AS SELECT a.name_id name, <<other columns from the sizes table>> FROM valid_sizes a, sizes b WHERE a.name_id = b.name_id </code></pre> As long as you operate through the view, it would seem that your could replicate the functionality reasonably well. Now, if you admit PL/SQL solutions, you can create custom object types that could include logic to limit the set of values they can hold and to have methods to get the IDs and to get the values, etc.

375,154

How do I get the time a file was last modified in Python?

Assuming the file exists (using <code>os.path.exists(filename)</code> to first make sure that it does), how do I display the time a file was last modified? This is on Linux if that makes any difference.

375,168

3

0

null

2008-12-17 16:33:41.07 UTC

10

2018-02-24 16:17:13.153 UTC

2008-12-17 17:11:11.15 UTC

Bill the Lizard

1,288

Bill the Lizard

1,288

null

1

66

python|file|time

79,023

<a href="http://docs.python.org/library/os.html#os.stat" rel="noreferrer">os.stat()</a> <pre><code>import os filename = "/etc/fstab" statbuf = os.stat(filename) print("Modification time: {}".format(statbuf.st_mtime)) </code></pre> Linux does not record the creation time of a file (<a href="https://unix.stackexchange.com/q/24441/61642">for most fileystems</a>).

6,883,010

If I'm already using Modernizr, will I then even need HTML5 Shiv?

1) If I'm already using Modernizr, will I then even need HTML5 Shiv to enable HTML5 tag support for IE? 2) Is HTML5 Shiv only for IE, or for all browser who don't have native HTML 5 support? Like older versions of Firefox, Safari, Chrome, etc?

6,883,023

1

0

null

2011-07-30 12:09:42.083 UTC

10

2012-08-14 06:50:54.237 UTC

null

1,352,036

null

84,201

null

1

46

javascript|html|css|cross-browser|modernizr

18,354

<blockquote> 1) If I'm already using Modernizer then even will I need HTML5 Shiv to enable HTML5 tag supports for IE. </blockquote> You don't need to separately include <a href="http://code.google.com/p/html5shiv/" rel="noreferrer">html5shiv</a>, because Modernizr includes it: <blockquote> As of Modernizr 1.5, this script is identical to what is used in the popular html5shim/html5shiv library. </blockquote> <a href="http://www.modernizr.com/docs/#html5inie" rel="noreferrer">http://www.modernizr.com/docs/#html5inie</a> <hr> <blockquote> 2) and is HTML5 Shiv only for IE or for all browser who don't have native HTML 5 support. like older version of Firefox, Safari, Chrome etc. </blockquote> It's only for Internet Explorer. Older versions of other browsers don't need it: <a href="http://caniuse.com/html5semantic" rel="noreferrer">http://caniuse.com/html5semantic</a> And the recommended snippet to include it is: <pre><code> </code></pre> Which will only ever run for IE less than 9.

6,427,128

Why is Clojure named Clojure

Why is the name of the language, "Clojure"? I googled a bit, asked in #clojure. So far, no luck.

6,427,317

1

6

null

2011-06-21 14:39:25.857 UTC

2

2012-11-03 00:44:52.41 UTC

2011-10-02 23:38:49.407 UTC

null

168,868

null

31,830

null

1

56

clojure|jvm

3,794

Rich Hickey's (He's the designer of Clojure) comment on that is the 1st reference link on wiki: <blockquote> Did you pick the name based on starting with the word "closure" and replacing the "s" with "j" for Java? It seems pretty likely, but it would be nice to have that confirmed. The name was chosen to be unique. I wanted to involve c (c#), l (lisp) and j (java). Once I came up with Clojure, given the pun on closure, the available domains and vast emptiness of the googlespace, it was an easy decision. </blockquote> <a href="http://groups.google.com/group/clojure/msg/766b75baa7987850" rel="noreferrer">http://groups.google.com/group/clojure/msg/766b75baa7987850</a>

20,515,679

RequireJS: To Bundle or Not to Bundle

I'm using RequireJS for my web application. I'm using EmberJS for the application framework. I've come to a point where, I think, I should start bundling my application into a single js file. That is where I get a little confused: If I finally bundle everything into one file for deployment, then my whole application loads in one shot, instead of on demand. Isn't bundling contradictory to AMD in general and RequireJS in particular? What further confuses me, is what I found on the <a href="http://requirejs.org/docs/start.html#optimize" rel="nofollow noreferrer">RequireJS</a> website: <blockquote> Once you are finished doing development and want to deploy your code for your end users, you can use the optimizer to combine the JavaScript files together and minify it. In the example above, it can combine main.js and helper/util.js into one file and minify the result. </blockquote> I found this <a href="https://stackoverflow.com/questions/12232848/when-to-use-requirejs-and-when-to-use-bundled-javascript">similar thread</a> but it doesn't answer my question.

20,518,314

2

0

null

2013-12-11 09:45:05.297 UTC

9

2014-02-02 20:42:27.327 UTC

2017-05-23 10:31:12.597 UTC

null

-1

null

1,046,810

null

1

12

requirejs

2,696

<blockquote> If I finally bundle everything into one file for deployment, then my whole application loads in one shot, instead of on demand. Isn't bundling contradictory to AMD in general and RequireJS in particular? </blockquote> It is not contradictory. Loading modules on demand is only one benefit of RequireJS. A greater benefit in my book is that modularization helps to use a divide-and-conquer approach. We can look at it in this way: even though all the functions and classes we put in a single file do not benefit from loading on demand, we still write multiple functions and multiple classes because it helps break down the problem in a structured way. However, the multiplicity of modules we create in development do not necessarily make sense when running the application in a browser. The greatest cost of on-demand loading is sending multiple HTTP requests over the wire. Let's say your application has 10 modules and you send 10 requests to load it because you load these modules individually. Your total cost is going to be the cost you have to pay to load the bytes from the 10 files (let's call it Pc for payload cost), plus an overhead cost for each HTTP request (let's call it Oc, for overhead cost). The overhead has to do with the data and computations that have to occur to initiate and close these requests. They are not insignificant. So you are paying Pc + 10*Oc. If you send everything in one chunk you pay Pc + 1*Oc. You've saved 9*Oc. In fact the savings are probably greater because (since compression is often used at both ends to reduce the size of the data transmitted) compression is going to provide greater benefits if the entire data is compressed together than if it is compressed as 10 chunks. (Note: the above analysis omits details that are not useful to cover.) Someone might object: "But you are comparing loading all the modules in separately versus loading all the modules in one chunk. If we load on demand then we won't load all the modules." As a matter of fact, most applications have a core of modules that will always be loaded, no matter what. These are the modules without which the application won't work at all. For some small applications this means all modules, so it make sense to bundle all of them together. For bigger applications, this means that a core set of modules will be used every single time the application runs, but a small set will be used only on occasion. In the latter case, the optimization should create multiple bundles. I have an <a href="https://github.com/mangalam-research/wed">application</a> like this. It is an editor with modes for various editing needs. A good 90% of the modules belong to the core. They are going to be loaded and used anyway so it makes sense to bundle them. The code for the modes themselves is not always going to be used but all the files for a given mode are going to be needed if the mode is loaded at all so each mode should be its own bundle. So in this case a model with one core bundle and a series of mode bundles makes sense to a) optimize the deployed application but b) keep some of the benefits of loading on demand. That's the beauty of RequireJS: it does not require to do one or the other exclusively.

20,454,115

Where does Windows store the settings for Scheduled Tasks console?

I would like to know where Windows stores information for Scheduled Tasks. I would like to be able to find the reference for the name, schedule, or command to run associated with a given task. This may not be practical or possible, but I would also like a means to edit the scheduled tasks and their attributes outside the Schedule Tasks console. I've assumed that the data would be in the Registry somewhere, since I doubt it would be stored in a normal file, but I'm uncertain where I should be looking.

20,454,183

3

0

null

2013-12-08 13:44:28.78 UTC

8

2018-03-30 23:10:03.433 UTC

2015-05-19 19:44:30.577 UTC

null

868,354

null

3,078,605

null

1

27

windows|scheduled-tasks

99,211

Windows stores scheduled tasks as XML files, AND in the registry. You can find them in a few places: Filesystem: <blockquote> %systemroot%\System32\Tasks %systemroot%\Tasks </blockquote> Registry: <blockquote> HKLM\Software\Microsoft\Windows NT\CurrentVersion\Schedule\Taskcache\Tasks HKLM\Software\Microsoft\Windows NT\CurrentVersion\Schedule\Taskcache\Tree </blockquote> Note: You can't edit the XML files directly in \Tasks for security reasons. See here for more information: <a href="https://serverfault.com/questions/440496/ok-to-edit-tasks-xml-file-in-c-windows-system32-tasks">https://serverfault.com/questions/440496/ok-to-edit-tasks-xml-file-in-c-windows-system32-tasks</a> To work with importing the XML files without going through the scheduled task UI you can look at these: <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/bb736357%28v=vs.85%29.aspx" rel="noreferrer">Schtasks.exe</a> <a href="http://technet.microsoft.com/en-us/library/jj649816.aspx" rel="noreferrer">Powershell Scheduled Task Cmdlets</a>

20,425,724

Python+OpenCV: cv2.imwrite

I'm trying to detect a face and write down area with the face in a separate file. How can I do it? I think that i must use "faces" (you can see this var in code). But how? <pre><code>from ffnet import mlgraph, ffnet, tmlgraph, imlgraph import pylab import sys import cv,cv2 import numpy cascade = cv.Load('C:\opencv\data\haarcascades\haarcascade_frontalface_alt.xml') def detect(image): bitmap = cv.fromarray(image) faces = cv.HaarDetectObjects(bitmap, cascade, cv.CreateMemStorage(0)) if faces: for (x,y,w,h),n in faces: cv2.rectangle(image,(x,y),(x+w,y+h),(255,255,255),3) return image if __name__ == "__main__": cam = cv2.VideoCapture(0) while 1: _,frame =cam.read() frame = numpy.asarray(detect(frame)) cv2.imshow("features", frame) if cv2.waitKey(1) == 0x1b: # ESC print 'ESC pressed. Exiting ...' break </code></pre>

20,426,395

3

0

null

2013-12-06 13:59:03.343 UTC

18

2019-08-26 20:01:57.023 UTC

2014-03-08 12:43:46.24 UTC

null

2,255,305

null

3,074,695

null

1

29

python|opencv|python-2.7|numpy

164,293

This following code should extract face in images and save faces on disk <pre><code>def detect(image): image_faces = [] bitmap = cv.fromarray(image) faces = cv.HaarDetectObjects(bitmap, cascade, cv.CreateMemStorage(0)) if faces: for (x,y,w,h),n in faces: image_faces.append(image[y:(y+h), x:(x+w)]) #cv2.rectangle(image,(x,y),(x+w,y+h),(255,255,255),3) return image_faces if __name__ == "__main__": cam = cv2.VideoCapture(0) while 1: _,frame =cam.read() image_faces = [] image_faces = detect(frame) for i, face in enumerate(image_faces): cv2.imwrite("face-" + str(i) + ".jpg", face) #cv2.imshow("features", frame) if cv2.waitKey(1) == 0x1b: # ESC print 'ESC pressed. Exiting ...' break </code></pre>

42,744,280

GCC throws error upon compilation: error: unknown type name ‘FILE’

I am making a function which is just writes <code>"hello"</code> to a file. I have put it in a different file and included its header in the program. But gcc is giving an error namely: <blockquote> <code>error: unknown type name ‘FILE’.</code> </blockquote> The code is given below <code>app.c</code>: <pre><code>#include <stdio.h> #include <stdlib.h> #include "write_hello.h" int main() { FILE* fp; fp = fopen("new_file.txt", "w"); write_hello(fp); return 0; } </code></pre> <code>write_hello.h</code>: <pre><code>void write_hello(FILE*); </code></pre> <code>write_hello.c</code>: <pre><code>void write_hello(FILE* fp) { fprintf(fp, "hello"); printf("Done\n"); } </code></pre> when compiling by gcc the following occurs: <pre><code>harsh@harsh-Inspiron-3558:~/c/bank_management/include/test$ sudo gcc app.c write_hello.c -o app write_hello.c:3:18: error: unknown type name ‘FILE’ void write_hello(FILE* fp) { </code></pre>

42,744,341

1

null

2017-03-12 05:56:43.603 UTC

3

2021-07-22 19:10:12.26 UTC

null

4,298,200

null

4,982,988

null

1

9

c|gcc

46,424

FILE is defined in stdio.h and you need to include it in each file that uses it. So write_hello.h and write_hello.c should both include it, and write_hello.c should also include write_hello.h (since it implements the function defined in write_hello.h). Also note that it is standard practice for every header file is to define a macro of the same name (IN CAPS), and enclose the entire header between #ifndef, #endif. In C, this prevents a header from getting #included twice. This is known as the "internal include guard" (with thanks to Story Teller for pointing that out). All system headers such as stdio.h include an internal include guard. All user defined headers should also include an internal include guard as shown in the example below. write_hello.h <pre><code>#ifndef WRITE_HELLO_H #define WRITE_HELLO_H #include <stdio.h> void write_hello(FILE*); #endif </code></pre> write_hello.c <pre><code>#include <stdio.h> #include "write_hello.h" void write_hello(FILE* fp){ fprintf(fp,"hello"); printf("Done\n"); } </code></pre> Note that when you include system files, the header name is placed within <code><></code>'s. This helps the compiler identify that these headers are system headers which are stored in a central place based on your development environment. Your own custom headers are placed in quotes <code>""</code> are typically found in your current directory, but may be placed elsewhere by including the path, or adding the directory to your list of directories that the compiler searches. This is configurable within your project if you are using an IDE like NetBeans, or using the -I compiler option is building it directly or through a makefile.

42,843,441

Kotlin Error : Could not find org.jetbrains.kotlin:kotlin-stdlib-jre7:1.0.7

I installed the Kotlin plugin into my app (v. v1.1.1-release-Studio2.2-1) and then selected "Configure Kotlin in Project" I selected compiler and runtime version of 1.0.7. Kotlin updated my Gradle files. Now when I try to build in I get: <blockquote> Error: A problem occurred configuring project ':app'. Could not resolve all dependencies for configuration ':app:_debugApkCopy'. Could not find org.jetbrains.kotlin:kotlin-stdlib-jre7:1.0.7. Required by: MyApplication:app:unspecified </blockquote> I'm not sure what I'm missing here.

53,358,817

18

2

null

2017-03-16 19:42:36.99 UTC

11

2022-01-03 15:03:27.143 UTC

2020-06-20 09:12:55.06 UTC

null

-1

null

517,733

null

1

145

android|kotlin|android-gradle-plugin

210,971

replace <pre><code>implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version" ^ | JRE = Java Runtime Environment </code></pre> with <pre><code>implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" ^ | JDK = Java Development Kit </code></pre> Since the version with jre is absolute , just replace and sync the project Official Documentation <a href="http://kotlinlang.org/docs/reference/whatsnew12.html#kotlin-standard-library-artifacts-and-split-packages" rel="noreferrer">here</a> Thanks for the link @ <a href="https://stackoverflow.com/users/164966/r0manarmy">ROMANARMY</a>

13,399,981

.h264 sample file

I'm currently using files <a href="http://support.apple.com/kb/HT1425" rel="nofollow">here</a>, but I get some errors while testing my program. I just want to see if it fails only with this one or with all other .h264 files. So, are there any other sources where I can download (standard) .h264 sample files for test ? Thanks.

13,415,851

2

0

null

2012-11-15 14:50:37.013 UTC

2

2016-09-27 02:05:56.247 UTC

2015-03-12 15:14:23.283 UTC

null

619,860

null

619,860

null

1

video-streaming|h.264|video-encoding

41,340

Option 1: make your own with x264. These are not standard sample files, but you can control which parts of H.264 they use, for example different profile/level/etc, make them I-frame-only, make them have only a particular macroblock type, etc. Also you can make them tiny, e.g. one or a few frames long. Option 2: perhaps the JM software comes with some sample files? <a href="http://iphome.hhi.de/suehring/tml/" rel="nofollow">http://iphome.hhi.de/suehring/tml/</a> Option 3: if you want to test a large number of files, download some random trailers etc in mp4 formar and demux them to get raw .h264 (for example with ffmpeg -vcodec copy)

69,554,485

ESLint - Error: Must use import to load ES Module

I am currently setting up a boilerplate with React, TypeScript, styled components, <a href="https://en.wikipedia.org/wiki/Webpack" rel="nofollow noreferrer">Webpack</a>, etc., and I am getting an error when trying to run <a href="https://en.wikipedia.org/wiki/ESLint" rel="nofollow noreferrer">ESLint</a>: <blockquote> Error: Must use import to load ES Module </blockquote> Here is a more verbose version of the error: <pre class="lang-none prettyprint-override"><code>/Users/ben/Desktop/development projects/react-boilerplate-styled-context/src/api/api.ts 0:0 error Parsing error: Must use import to load ES Module: /Users/ben/Desktop/development projects/react-boilerplate-styled-context/node_modules/eslint/node_modules/eslint-scope/lib/definition.js require() of ES modules is not supported. require() of /Users/ben/Desktop/development projects/react-boilerplate-styled-context/node_modules/eslint/node_modules/eslint-scope/lib/definition.js from /Users/ben/Desktop/development projects/react-boilerplate-styled-context/node_modules/babel-eslint/lib/require-from-eslint.js is an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which defines all .js files in that package scope as ES modules. Instead rename definition.js to end in .cjs, change the requiring code to use import(), or remove "type": "module" from /Users/ben/Desktop/development projects/react-boilerplate-styled-context/node_modules/eslint/node_modules/eslint-scope/package.json </code></pre> The error occurs in every single one of my .js and .ts/ .tsx files where I only use <code>import</code> or the file doesn't even have an import at all. I understand what the error is saying, but I don't have any idea why it is being thrown when in fact I only use imports or even no imports at all in some files. Here is my package.json file where I trigger the linter from using <code>npm run lint:eslint:quiet</code>: <pre><code>{ "name": "my-react-boilerplate", "version": "1.0.0", "description": "", "main": "index.tsx", "directories": { "test": "test" }, "engines": { "node": ">=14.0.0" }, "type": "module", "scripts": { "build": "webpack --config webpack.prod.js", "dev": "webpack serve --config webpack.dev.js", "lint": "npm run typecheck && npm run lint:css && npm run lint:eslint:quiet", "lint:css": "stylelint './src/**/*.{js,ts,tsx}'", "lint:eslint:quiet": "eslint --ext .ts,.tsx,.js,.jsx ./src --no-error-on-unmatched-pattern --quiet", "lint:eslint": "eslint --ext .ts,.tsx,.js,.jsx ./src --no-error-on-unmatched-pattern", "lint:eslint:fix": "eslint --ext .ts,.tsx,.js,.jsx ./src --no-error-on-unmatched-pattern --quiet --fix", "test": "cross-env NODE_ENV=test jest --coverage", "test:watch": "cross-env NODE_ENV=test jest --watchAll", "typecheck": "tsc --noEmit", "precommit": "npm run lint" }, "lint-staged": { "*.{ts,tsx,js,jsx}": [ "npm run lint:eslint:fix", "git add --force" ], "*.{md,json}": [ "prettier --write", "git add --force" ] }, "husky": { "hooks": { "pre-commit": "npx lint-staged && npm run typecheck" } }, "resolutions": { "styled-components": "^5" }, "author": "", "license": "ISC", "devDependencies": { "@babel/core": "^7.5.4", "@babel/plugin-proposal-class-properties": "^7.5.0", "@babel/preset-env": "^7.5.4", "@babel/preset-react": "^7.0.0", "@types/history": "^4.7.6", "@types/react": "^17.0.29", "@types/react-dom": "^17.0.9", "@types/react-router": "^5.1.17", "@types/react-router-dom": "^5.1.5", "@types/styled-components": "^5.1.15", "@typescript-eslint/eslint-plugin": "^5.0.0", "babel-cli": "^6.26.0", "babel-eslint": "^10.0.2", "babel-loader": "^8.0.0-beta.6", "babel-polyfill": "^6.26.0", "babel-preset-env": "^1.7.0", "babel-preset-react": "^6.24.1", "babel-preset-stage-2": "^6.24.1", "clean-webpack-plugin": "^4.0.0", "dotenv-webpack": "^7.0.3", "error-overlay-webpack-plugin": "^1.0.0", "eslint": "^8.0.0", "eslint-config-airbnb": "^18.2.0", "eslint-config-prettier": "^8.3.0", "eslint-config-with-prettier": "^6.0.0", "eslint-plugin-compat": "^3.3.0", "eslint-plugin-import": "^2.25.2", "eslint-plugin-jsx-a11y": "^6.2.3", "eslint-plugin-prettier": "^4.0.0", "eslint-plugin-react": "^7.14.2", "eslint-plugin-react-hooks": "^4.2.0", "extract-text-webpack-plugin": "^3.0.2", "file-loader": "^6.2.0", "html-webpack-plugin": "^5.3.2", "husky": "^7.0.2", "prettier": "^2.4.1", "raw-loader": "^4.0.2", "style-loader": "^3.3.0", "stylelint": "^13.13.1", "stylelint-config-recommended": "^5.0.0", "stylelint-config-styled-components": "^0.1.1", "stylelint-processor-styled-components": "^1.10.0", "ts-loader": "^9.2.6", "tslint": "^6.1.3", "typescript": "^4.4.4", "url-loader": "^4.1.1", "webpack": "^5.58.2", "webpack-cli": "^4.2.0", "webpack-dev-server": "^4.3.1", "webpack-merge": "^5.3.0" }, "dependencies": { "history": "^4.10.0", "process": "^0.11.10", "react": "^17.0.1", "react-dom": "^17.0.1", "react-router-dom": "^5.2.0", "styled-components": "^5.2.1" } } </code></pre> Here is my .eslintrc file: <pre><code>{ "extends": ["airbnb", "prettier"], "parser": "babel-eslint", "plugins": ["prettier", "@typescript-eslint"], "parserOptions": { "ecmaVersion": 8, "ecmaFeatures": { "experimentalObjectRestSpread": true, "impliedStrict": true, "classes": true } }, "env": { "browser": true, "node": true, "jest": true }, "rules": { "arrow-body-style": ["error", "as-needed"], "class-methods-use-this": 0, "react/jsx-filename-extension": 0, "global-require": 0, "react/destructuring-assignment": 0, "import/named": 2, "linebreak-style": 0, "import/no-dynamic-require": 0, "import/no-named-as-default": 0, "import/no-unresolved": 2, "import/prefer-default-export": 0, "semi": [2, "always"], "max-len": [ "error", { "code": 80, "ignoreUrls": true, "ignoreComments": true, "ignoreStrings": true, "ignoreTemplateLiterals": true } ], "new-cap": [ 2, { "capIsNew": false, "newIsCap": true } ], "no-param-reassign": 0, "no-shadow": 0, "no-tabs": 2, "no-underscore-dangle": 0, "react/forbid-prop-types": [ "error", { "forbid": ["any"] } ], "import/no-extraneous-dependencies": ["error", { "devDependencies": true }], "react/jsx-no-bind": [ "error", { "ignoreRefs": true, "allowArrowFunctions": true, "allowBind": false } ], "react/no-unknown-property": [ 2, { "ignore": ["itemscope", "itemtype", "itemprop"] } ] } } </code></pre> And I’m not sure if it is relevant, but here is also my tsconfig.eslint.json file: <pre><code>{ "extends": "./tsconfig.json", "include": ["./src/**/*.ts", "./src/**/*.tsx", "./src/**/*.js"], "exclude": ["node_modules/**", "build/**", "coverage/**"] } </code></pre> How can I fix this? Googling the error does not present any useful forums or raised bugs. Most of them just state not to use <code>require</code> in your files which I am not.

69,557,309

7

0

null

2021-10-13 11:14:45.797 UTC

20

2022-09-22 13:42:13.977 UTC

2022-08-21 22:38:48.797 UTC

null

63,550

null

3,955,685

null

1

152

javascript|node.js|reactjs|eslint

86,746

I think the problem is that you are trying to use the deprecated <a href="https://github.com/babel/babel-eslint" rel="noreferrer">babel-eslint parser</a>, last updated a year ago, which looks like it doesn't support ES6 modules. Updating to the <a href="https://github.com/babel/babel/tree/main/eslint/babel-eslint-parser" rel="noreferrer">latest parser</a> seems to work, at least for simple linting. So, do this: <ul> <li>In package.json, update the line <code>"babel-eslint": "^10.0.2",</code> to <code>"@babel/eslint-parser": "^7.5.4",</code>. This works with the code above but it may be better to use the latest version, which at the time of writing is 7.16.3.</li> <li>Run <code>npm i</code> from a terminal/command prompt in the folder</li> <li>In .eslintrc, update the parser line <code>"parser": "babel-eslint",</code> to <code>"parser": "@babel/eslint-parser",</code></li> <li>In .eslintrc, add <code>"requireConfigFile": false,</code> to the parserOptions section (underneath <code>"ecmaVersion": 8,</code>) (I needed this or babel was looking for config files I don't have)</li> <li>Run the command to lint a file</li> </ul> Then, for me with just your two configuration files, the error goes away and I get appropriate linting errors.

41,449,617

Why is sum so much faster than inject(:+)?

So I was running some benchmarks in Ruby 2.4.0 and realized that <pre><code>(1...1000000000000000000000000000000).sum </code></pre> calculates immediately whereas <pre><code>(1...1000000000000000000000000000000).inject(:+) </code></pre> takes so long that I just aborted the operation. I was under the impression that <code>Range#sum</code> was an alias for <code>Range#inject(:+)</code> but it seems like that is not true. So how does <code>sum</code> work, and why is it so much faster than <code>inject(:+)</code>? N.B. The documentation for <code>Enumerable#sum</code> (which is implemented by <code>Range</code>) does not say anything about lazy evaluation or anything along those lines.

41,449,844

1

0

null

2017-01-03 17:59:33.62 UTC

25

2017-01-05 23:51:26.887 UTC

2017-01-04 04:04:01.713 UTC

null

5,021,321

null

5,021,321

null

1

132

ruby

9,109

<h1>Short answer</h1> For an integer range : <ul> <li><code>Enumerable#sum</code> returns <code>(range.max-range.min+1)*(range.max+range.min)/2</code></li> <li><code>Enumerable#inject(:+)</code> iterates over every element.</li> </ul> <hr> <h1>Theory</h1> The sum of integers between 1 and <code>n</code> is called a <a href="https://en.wikipedia.org/wiki/Triangular_number">triangular number</a>, and is equal to <code>n*(n+1)/2</code>. The sum of integers between <code>n</code> and <code>m</code> is the triangular number of <code>m</code> minus the triangular number of <code>n-1</code>, which is equal to <code>m*(m+1)/2-n*(n-1)/2</code>, and can be written <code>(m-n+1)*(m+n)/2</code>. <h1>Enumerable#sum in Ruby 2.4</h1> This property in used in <a href="http://ruby-doc.org/core-2.4.0/Enumerable.html#method-i-sum"><code>Enumerable#sum</code></a> for integer ranges : <pre><code>if (RTEST(rb_range_values(obj, &beg, &end, &excl))) { if (!memo.block_given && !memo.float_value && (FIXNUM_P(beg) || RB_TYPE_P(beg, T_BIGNUM)) && (FIXNUM_P(end) || RB_TYPE_P(end, T_BIGNUM))) { return int_range_sum(beg, end, excl, memo.v); } } </code></pre> <code>int_range_sum</code> looks like this : <pre><code>VALUE a; a = rb_int_plus(rb_int_minus(end, beg), LONG2FIX(1)); a = rb_int_mul(a, rb_int_plus(end, beg)); a = rb_int_idiv(a, LONG2FIX(2)); return rb_int_plus(init, a); </code></pre> which is equivalent to: <pre><code>(range.max-range.min+1)*(range.max+range.min)/2 </code></pre> the aforementioned equality! <h1>Complexity</h1> Thanks a lot to @k_g and @Hynek-Pichi-Vychodil for this part! <h3>sum</h3> <code>(1...1000000000000000000000000000000).sum</code> requires three additions, a multiplication, a substraction and a division. It's a constant number of operations, but multiplication is O((log n)²), so <code>Enumerable#sum</code> is O((log n)²) for an integer range. <h3>inject</h3> <code>(1...1000000000000000000000000000000).inject(:+)</code> requires 999999999999999999999999999998 additions! Addition is O(log n), so <code>Enumerable#inject</code> is O(n log n). With <code>1E30</code> as input, <code>inject</code> with never return. The sun will explode long before! <h1>Test</h1> It's easy to check if Ruby Integers are being added : <pre><code>module AdditionInspector def +(b) puts "Calculating #{self}+#{b}" super end end class Integer prepend AdditionInspector end puts (1..5).sum #=> 15 puts (1..5).inject(:+) # Calculating 1+2 # Calculating 3+3 # Calculating 6+4 # Calculating 10+5 #=> 15 </code></pre> Indeed, from <code>enum.c</code> comments : <blockquote> <code>Enumerable#sum</code> method may not respect method redefinition of <code>"+"</code> methods such as <code>Integer#+</code>. </blockquote>

5,935,638

Autocomplete Textbox Example in python + Google app engine

For my google app engine application, I need to include a autocompleter Textbox which will show the name starting with the textbox value.And the name will retrieve from the google app engine datastore. Any good tutorial or sample code please. Update: Please Answer for this I created a sample HTML code : <a href="http://dl.dropbox.com/u/7384181/autocomplete/autocomplete.html" rel="nofollow">dl.dropbox.com/u/7384181/autocomplete/autocomplete.html</a> . In this html page i have creating the textbox dinamically.So currently i assign the autocomplete in the first textbox(txtProduct1) only. How do i assign the autocomplete in rest all the textbox which is going to create dynamically ?

5,936,103

3

1

null

2011-05-09 10:34:02.03 UTC

9

2011-10-25 21:02:45.96 UTC

null

59,470

null

783,657

null

1

6

python|ajax|google-app-engine|autocomplete

5,304

You can have a look at the jquery auto complete <a href="http://docs.jquery.com/Plugins/autocomplete" rel="noreferrer">here</a> HTML : <pre><code>$("#search_users").autocomplete(/search/search_manager); </code></pre> python-controller: jquery autocomplete plugin by default uses variable q <pre><code>class search_user(webapp.RequestHandler): q = (self.request.GET['q']).lower() results=models.user.all().fetch(100) for records in result: print records+"|"+records+"\n" application = webapp.WSGIApplication([ (r'/user_auth/search_manager',search_user)] def main(): run_wsgi_app(application) if __name__ == '__main__': main() simple: </code></pre> Apply the autocomplete to a class $ <pre><code>(".search_users").autocomplete(/search/search_manager); </code></pre>

6,003,648

Preload a website

I'm looking to preload a website. I only want a loading bar once on the site. When its loading I want every page to pre load. How would I do this? <a href="http://frankadvertisingus.com/fa_website/home.html" rel="nofollow">http://frankadvertisingus.com/fa_website/home.html</a>

6,003,778

4

3

null

2011-05-14 17:38:31.09 UTC

null

2016-08-27 19:11:14.69 UTC

2011-05-14 17:55:08.733 UTC

null

743,171

null

743,171

null

1

0

javascript|jquery|html|web|dreamweaver

44,325

A Right Click for Source code can be helpful Here is the source where you can find the jQuery for it. <a href="https://web.archive.org/web/20110511045013/http://www.gayadesign.com/diy/queryloader-preload-your-website-in-style/" rel="nofollow noreferrer">http://www.gayadesign.com/diy/queryloader-preload-your-website-in-style/</a>

5,851,213

Crawling with an authenticated session in Scrapy

In my <a href="https://stackoverflow.com/q/5850755/445210">previous question</a>, I wasn't very specific over my problem (scraping with an authenticated session with Scrapy), in the hopes of being able to deduce the solution from a more general answer. I should probably rather have used the word <code>crawling</code>. So, here is my code so far: <pre><code>class MySpider(CrawlSpider): name = 'myspider' allowed_domains = ['domain.com'] start_urls = ['http://www.domain.com/login/'] rules = ( Rule(SgmlLinkExtractor(allow=r'-\w+.html$'), callback='parse_item', follow=True), ) def parse(self, response): hxs = HtmlXPathSelector(response) if not "Hi Herman" in response.body: return self.login(response) else: return self.parse_item(response) def login(self, response): return [FormRequest.from_response(response, formdata={'name': 'herman', 'password': 'password'}, callback=self.parse)] def parse_item(self, response): i['url'] = response.url # ... do more things return i </code></pre> As you can see, the first page I visit is the login page. If I'm not authenticated yet (in the <code>parse</code> function), I call my custom <code>login</code> function, which posts to the login form. Then, if I am authenticated, I want to continue crawling. The problem is that the <code>parse</code> function I tried to override in order to log in, now no longer makes the necessary calls to scrape any further pages (I'm assuming). And I'm not sure how to go about saving the Items that I create. Anyone done something like this before? (Authenticate, then crawl, using a <code>CrawlSpider</code>) Any help would be appreciated.

5,857,202

4

null

2011-05-01 20:34:32.713 UTC

42

2018-03-19 09:21:36.877 UTC

2017-05-23 12:25:21.27 UTC

null

-1

null

445,210

null

1

33

python|scrapy

38,529

Do not override the <code>parse</code> function in a <code>CrawlSpider</code>: When you are using a <code>CrawlSpider</code>, you shouldn't override the <code>parse</code> function. There's a warning in the <code>CrawlSpider</code> documentation here: <a href="http://doc.scrapy.org/en/0.14/topics/spiders.html#scrapy.contrib.spiders.Rule" rel="noreferrer">http://doc.scrapy.org/en/0.14/topics/spiders.html#scrapy.contrib.spiders.Rule</a> This is because with a <code>CrawlSpider</code>, <code>parse</code> (the default callback of any request) sends the response to be processed by the <code>Rule</code>s. <hr> Logging in before crawling: In order to have some kind of initialisation before a spider starts crawling, you can use an <code>InitSpider</code> (which inherits from a <code>CrawlSpider</code>), and override the <code>init_request</code> function. This function will be called when the spider is initialising, and before it starts crawling. In order for the Spider to begin crawling, you need to call <code>self.initialized</code>. You can read the code that's responsible for this <a href="https://github.com/scrapy/scrapy/blob/master/scrapy/spiders/init.py" rel="noreferrer">here</a> (it has helpful docstrings). <hr> An example: <pre><code>from scrapy.contrib.spiders.init import InitSpider from scrapy.http import Request, FormRequest from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor from scrapy.contrib.spiders import Rule class MySpider(InitSpider): name = 'myspider' allowed_domains = ['example.com'] login_page = 'http://www.example.com/login' start_urls = ['http://www.example.com/useful_page/', 'http://www.example.com/another_useful_page/'] rules = ( Rule(SgmlLinkExtractor(allow=r'-\w+.html$'), callback='parse_item', follow=True), ) def init_request(self): """This function is called before crawling starts.""" return Request(url=self.login_page, callback=self.login) def login(self, response): """Generate a login request.""" return FormRequest.from_response(response, formdata={'name': 'herman', 'password': 'password'}, callback=self.check_login_response) def check_login_response(self, response): """Check the response returned by a login request to see if we are successfully logged in. """ if "Hi Herman" in response.body: self.log("Successfully logged in. Let's start crawling!") # Now the crawling can begin.. return self.initialized() else: self.log("Bad times :(") # Something went wrong, we couldn't log in, so nothing happens. def parse_item(self, response): # Scrape data from page </code></pre> <hr> Saving items: Items your Spider returns are passed along to the Pipeline which is responsible for doing whatever you want done with the data. I recommend you read the documentation: <a href="http://doc.scrapy.org/en/0.14/topics/item-pipeline.html" rel="noreferrer">http://doc.scrapy.org/en/0.14/topics/item-pipeline.html</a> If you have any problems/questions in regards to <code>Item</code>s, don't hesitate to pop open a new question and I'll do my best to help.

34,575,732

Setting space between some items in stack view

In Interface Builder, I use a horizontal UIStackView and want to place the items as this : <pre><code> xx xx xx </code></pre> every x symbolize an item. Item1 and item2 should be stuck one to the other, but item2 and item3 should be spaced and so on. That means I do not want constant spacing between all the items. How can I do so ? (maybe an equivalent of flexible space of toolbars) Thanks !

34,576,034

7

1

null

2016-01-03 10:57:07.2 UTC

5

2021-05-26 09:19:57 UTC

2016-01-03 11:14:04.923 UTC

null

5,658,452

null

5,658,452

null

1

60

ios|xcode

54,894

Inside your horizontal stack view have three more horizontal stack views so that you can have control over spacing and distribution for each item. See screenshot below: <a href="https://i.stack.imgur.com/EpEhj.png" rel="noreferrer"><img src="https://i.stack.imgur.com/EpEhj.png" alt="enter image description here"></a>

45,874,742

Android Color Notification Icon

I'm working on an app where I create a notification for the user. I want the icon to appear as white when it's in the status bar, but colored blue when it's being displayed in the drop down notification menu. Here's an example of the same thing being done by the Google Store app. White notification in status bar: <a href="https://i.stack.imgur.com/fcIS1.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/fcIS1.jpg" alt="enter image description here"></a> Colored notification in drop down menu: <a href="https://i.stack.imgur.com/tYmdz.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/tYmdz.jpg" alt="enter image description here"></a> How can I replicate this? What properties do I have to set? Edit: Here's my current code - I made the image all white with a transparent background, so it looks fine in the status bar, but in the notification drop, the image is still the same white color: <pre><code>private NotificationCompat.Builder getNotificationBuilder() { return new NotificationCompat.Builder(mainActivity) .setDeleteIntent(deletedPendingIntent) .setContentIntent(startChatPendingIntent) .setAutoCancel(true) .setSmallIcon(R.drawable.skylight_notification) .setColor(ContextCompat.getColor(mainActivity, R.color.colorPrimary)) .setContentTitle(mainActivity.getString(R.string.notification_title)) .setContentText(mainActivity.getString(R.string.notification_prompt)); } </code></pre>

45,883,564

10

2

null

2017-08-25 05:07:24.26 UTC

14

2021-07-08 07:19:40.833 UTC

2017-08-25 05:20:36.657 UTC

null

4,394,594

null

4,394,594

null

1

67

java|android|colors|push-notification|android-notifications

80,629

I found the answer to my question here: <a href="https://stackoverflow.com/a/44950197/4394594">https://stackoverflow.com/a/44950197/4394594</a> I don't know entirely what the problem was, but by putting the huge png that I was using for the icon into the this tool <a href="https://romannurik.github.io/AndroidAssetStudio/icons-notification.html#source.type=image&source.space.trim=1&source.space.pad=0&name=ic_skylight_notification" rel="noreferrer">https://romannurik.github.io/AndroidAssetStudio/icons-notification.html#source.type=image&source.space.trim=1&source.space.pad=0&name=ic_skylight_notification</a> and by placing the generated icons it gave into my mipmap folder, I was able to get the <code>setColor(...)</code> property to work correctly.

28,994,316

Can you add a custom message to AssertJ assertThat?

We have a test suite that primarily uses JUnit assertions with Hamcrest matchers. One of our team started experimenting with <a href="http://joel-costigliola.github.io/assertj/">AssertJ</a> and impressed people with its syntax, flexibility and declarative-ness. There is one feature that JUnit provides that I can't find an equivalent for in AssertJ: adding a custom assert failure message. We're often comparing objects that are not made for human readability and will have random-seeming Ids or UUIDs and it's impossible to tell what they're supposed to be by the data they contain. This is an unavoidable situation for our codebase, sadly, as part of the purpose it fulfills is mapping data between other services without necessarily understanding what it is. In JUnit, the <a href="http://junit.org/apidocs/org/junit/Assert.html#assertThat(java.lang.String,%20T,%20org.hamcrest.Matcher)"><code>assertThat</code></a> method provides a version with a <code>String reason</code> parameter before the <code>Matcher<T></code> param. This makes it trivial to add a short debug string shedding some light on the problem, like what the comparison should mean to a human. AssertJ, on the other hand, provides a jillion different <a href="http://joel-costigliola.github.io/assertj/core/api/org/assertj/core/api/Assertions.html#assertThat(org.assertj.core.api.AssertProvider)">genericized <code>static assertThat</code></a> methods which return some form of <a href="http://joel-costigliola.github.io/assertj/core/api/org/assertj/core/api/Assert.html">interface Assert</a> or one of its many implementing classes. This interface does not provide a standard way of setting a custom message to be included with failures. Is there any way to get this functionality from the AssertJ API or one of its extensions without having to <a href="http://joel-costigliola.github.io/assertj/assertj-core-custom-assertions.html">create a custom assert class for every assert type</a> we want to add messages to?

28,994,810

4

1

null

2015-03-11 18:14:26.397 UTC

13

2022-09-06 09:26:38.81 UTC

null

1,146,608

null

1

130

java|unit-testing|junit|assertj

50,298

And in classic fashion, I found what I was looking for moments after posting the question. Hopefully this will make it easier for the next person to find without first having to know what it's called. The magic method is the deceptively short-named <a href="https://joel-costigliola.github.io/assertj/core/api/org/assertj/core/api/AbstractAssert.html#as(java.lang.String,%20java.lang.Object...)" rel="noreferrer"><code>as</code></a>, which is part of another interface that <code>AbstractAssert</code> implements: <a href="https://joel-costigliola.github.io/assertj/core/api/org/assertj/core/api/Descriptable.html" rel="noreferrer">Descriptable</a>, not the base Assert interface. <blockquote> <code>public S as(String description, Object... args)</code> Sets the description of this object supporting <code>String.format(String, Object...)</code> syntax. Example : <pre><code>try { // set a bad age to Mr Frodo which is really 33 years old. frodo.setAge(50); // you can specify a test description with as() method or describedAs(), it supports String format args assertThat(frodo.getAge()).as("check %s's age", frodo.getName()).isEqualTo(33); } catch (AssertionError e) { assertThat(e).hasMessage("[check Frodo's age] expected:<[33]> but was:<[50]>"); } </code></pre> </blockquote> Where that quoted string in the catch block <code>hasMessage</code> is what appears in your unit test output log if the assertion fails. <hr> I found this by noticing the <code>failWithMessage</code> helper in the <a href="https://joel-costigliola.github.io/assertj/assertj-core-custom-assertions.html" rel="noreferrer">custom assert page</a> linked in the question. The <a href="https://joel-costigliola.github.io/assertj/core/api/org/assertj/core/api/AbstractAssert.html#failWithMessage(java.lang.String,%20java.lang.Object...)" rel="noreferrer">JavaDoc</a> for that method points out that it is protected, so it can't be used by callers to set a custom message. It does however mention the <code>as</code> helper: <blockquote> Moreover, this method honors any description set with <code>as(String, Object...)</code> or overridden error message defined by the user with <code>overridingErrorMessage(String, Object...)</code>. </blockquote> ... and the <a href="https://joel-costigliola.github.io/assertj/core/api/org/assertj/core/api/AbstractAssert.html#overridingErrorMessage(java.lang.String,%20java.lang.Object...)" rel="noreferrer">overridingErrorMessage</a> helper, which completely replaces the standard AssertJ <code>expected: ... but was:...</code> message with the new string provided. The AssertJ homepage doesn't mention either helper until the features highlights page, which shows examples of the <code>as</code> helper in the <a href="https://joel-costigliola.github.io/assertj/assertj-core-features-highlight.html#soft-assertions" rel="noreferrer">Soft Assertions</a> section, but doesn't directly describe what it does.

29,172,558

Why doesn't incrementing Nullable<int> throw an exception?

Could you please explain, why does Console.WriteLine write empty line (<code>Console.WriteLine(null)</code> give me compilation error) and why there isn't NullReferenceException (even <code>a+=1</code> shouldn't raise it)? <pre><code>int? a = null; a++; // Why there is not NullReferenceException? Console.WriteLine(a); // Empty line </code></pre>

29,172,637

3

2

null

2015-03-20 17:33:26.06 UTC

5

2015-04-14 13:15:19.73 UTC

2015-03-20 23:06:23.463 UTC

null

1,350,209

null

2,524,304

null

1

99

c#|.net|nullable

6,510

You're observing the effects of a lifted operator. From section 7.3.7 of the C# 5 specification: <blockquote> Lifted operators permit predefined and user-defined operators that operate on non-nullable value types to also be used with nullable forms of those types. Lifted operators are constructed from predefined and user-defined operators that meet certain requirements, as described in the following: <ul> <li>For the unary operators <code>+ ++ - -- ! ~</code> a lifted form of an operator exists if the operand and result types are both non-nullable value types. The lifted form is constructed by adding a single <code>?</code> modifier to the operand and result types. The lifted operator produces a null value if the operand is null. Otherwise, the lifted operator unwraps the operand, applies the underlying operator, and wraps the result.</li> </ul> </blockquote> So basically, <code>a++</code> in this case is an expression with a result of <code>null</code> (as an <code>int?</code>) and the variable is left untouched. When you call <pre><code>Console.WriteLine(a); </code></pre> that's being boxed into <code>object</code>, which converts it to a null reference, which is printed as an empty line.

32,344,232

Unable to Install Any Package in Visual Studio 2015

I've tried every package I could possibly find and none of them will install in my project. I've installed every update listed in the Extensions and Updates list that were available. When I attempt to install SendGrid for example, this is the result (as is the result with all other packages): <pre><code>Attempting to gather dependencies information for package 'Sendgrid.6.1.0' with respect to project 'UI\MyApplication.MVC', targeting '.NETFramework,Version=v4.5.2' Attempting to resolve dependencies for package 'Sendgrid.6.1.0' with DependencyBehavior 'Lowest' Resolving actions to install package 'Sendgrid.6.1.0' Resolved actions to install package 'Sendgrid.6.1.0' For adding package 'SendGrid.SmtpApi.1.3.1' to project 'MyApplication.MVC' that targets 'net452'. For adding package 'SendGrid.SmtpApi.1.3.1' to project 'MyApplication.MVC' that targets 'net452'. Adding package 'SendGrid.SmtpApi.1.3.1' to folder 'C:\Users\Keith\Source\Workspaces\MyApplication\MyApplication.MVC\packages' Install failed. Rolling back... </code></pre> I can't be the only one on the planet having issue with Visual Studio 2015 and the new and "improved" NuGet Package Manager. UPDATE: Well, must be something odd in my solution because I created a new project from the VS2015 template (web) and the packages install just fine. When I find out the issue, I'll post the resolution in the event others run into the same problem. UPDATE 2: Ok, it's not our solution. We created a new solution from scratch again (this has wasted a lot of our development time might I add), added a couple of packages (Identity, EF, SendGrid) and after checking the solution in to VSO, another developer performs a fresh creation of the branch and build errors occur. When I go to the NuGet packages for an individual project, it acts as though none of the packages I have added are available. Anyone else experiencing this?

36,461,793

19

1

null

2015-09-02 03:32:52.917 UTC

23

2020-02-24 09:31:19.473 UTC

2015-09-03 02:15:12.527 UTC

null

176,806

null

176,806

null

1

187

package|nuget|visual-studio-2015

121,734

tl;dr - Delete this: <pre><code>%AppData%/Nuget/Nuget.config </code></pre> Warning: If you had custom NuGet sources, this will remove them, and you'll have to re-add them. <hr> Longer version: You might have corrupted your NuGet config. Oh no :( Nuget.config is a file used to keep track of all of the places that NuGet pulls from, as well as configuring other things. More likely than not, this xml file got broken somehow. <ul> <li>Go to this path: <code>C:\Users\{{username}}\AppData\Roaming\</code></li> <li>Delete <code>Nuget.config</code></li> <li>Restart VS for good measure</li> </ul> <hr> For reference: in the good days of 2017, your file should look something like this <pre class="lang-xml prettyprint-override"><code><?xml version="1.0" encoding="utf-8"?> <configuration> <packageRestore> <add key="enabled" value="True" /> <add key="automatic" value="True" /> </packageRestore> <activePackageSource> <add key="nuget.org" value="https://api.nuget.org/v3/index.json" /> </activePackageSource> <packageSources> <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" /> <add key="nuget.org" value="https://www.nuget.org/api/v2/" />  </packageSources> <packageSourceCredentials>  </packageSourceCredentials> </configuration> </code></pre>

5,789,879

Does a replacement for Gallery widget with View recycling exist?

The default Gallery widget on Android does not recycle views - everytime the view for a new position is called the widget always calls the <code>getView</code> method of the adapter with <code>convertView</code> set to null. As you scroll backwards and forwards this ends up in lots of views being created, which the recycler component that the Gallery stores them in does not seem to recycle them quickly enough leading to an OOM situation. You can test this easily with a few large-ish images as your gallery items, but just a TextView will cause it in the end. Put a log statement with a counter in the <code>getView</code> method of your adapter also to see how many new views are created. Does a third-party widget which behaves like a Gallery but that also implements view recycling exist?

5,882,944

5

2

null

2011-04-26 11:52:29.257 UTC

12

2014-01-13 23:25:29.563 UTC

2011-08-18 10:34:03.427 UTC

null

114,066

null

290,028

null

1

12

android|view|gallery|out-of-memory|recycle

9,736

My solution was, in the end, going with @CommonsWare's suggestion to modify the Gallery source code. This is also required copying the following files: <ul> <li><code>AdapterView</code></li> <li><code>AbsSpinner</code></li> </ul> but these are pretty simple. After that I modified code to do the following: <blockquote> <code>RecycleBin</code> (<code>AbsSpinner</code>) <ul> <li>Place objects in the recycler one after another, rather than according to position</li> <li>Retrieve objects from the bottom of the recycler, regardless of the position requested</li> <li>The existing implementation assumed that each different position in the adapter resulted in a unique view. The changes above are only good if your Gallery contains only one type of item, if not you'll need to add some sort of key based on item type and the amount of that type required</li> </ul> <code>Gallery</code> <ul> <li>Used reflection (ugh) to modify the private <code>mGroupFlags</code> variable of <code>ViewGroup</code> to allow child re-ordering - I also set a boolean value indicating whether the field access succeeded which I test before using the component.</li> <li>Removed all calls to <code>mRecycler.clear()</code></li> <li>The number of items the gallery has to display changes as it scrolls and the existing implementation would clear the recycler when (a) setSelection was called (b) a motion scroll occurred</li> </ul> </blockquote> With these modifications my counter in my <code>newView</code> method in my adapter reached... 7. <a href="http://pastebin.com/FWyYTt4D">Here is the code</a> (Placed in the public domain 2013/08/07 under <a href="http://en.wikipedia.org/wiki/WTFPL">http://en.wikipedia.org/wiki/WTFPL</a>)

6,259,745

Volatile variable in Java

So I am reading this book titled Java Concurrency in Practice and I am stuck on this one explanation which I cannot seem to comprehend without an example. This is the quote: <blockquote> When thread <code>A</code> writes to a volatile variable and subsequently thread <code>B</code> reads that same variable, the values of all variables that were visible to <code>A</code> prior to writing to the volatile variable become visible to <code>B</code> after reading the volatile variable. </blockquote> Can someone give me a counterexample of why "the values of ALL variables that were visible to <code>A</code> prior to writing to the volatile variable become visible to <code>B</code> AFTER reading the volatile variable"? I am confused why all other non-volatile variables do not become visible to <code>B</code> before reading the volatile variable?

6,259,761

5

3

null

2011-06-07 01:17:31.79 UTC

16

2015-12-17 11:23:27.097 UTC

null

2,093,236

null

364,253

null

1

23

java|multithreading|concurrency|volatile

15,208

Thread B may have a CPU-local cache of those variables. A read of a volatile variable ensures that any intermediate cache flush from a previous write to the volatile is observed. For an example, read the following link, which concludes with "Fixing Double-Checked Locking using Volatile": <a href="http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html">http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html</a>

6,020,450

Oracle PL/SQL - Raise User-Defined Exception With Custom SQLERRM

Is it possible to create user-defined exceptions and be able to change the SQLERRM? For example: <pre><code>DECLARE ex_custom EXCEPTION; BEGIN RAISE ex_custom; EXCEPTION WHEN ex_custom THEN DBMS_OUTPUT.PUT_LINE(SQLERRM); END; / </code></pre> The output is "User-Defined Exception". Is it possible to change that message? EDIT: Here is some more detail. I hope this one illustrates what I'm trying to do better. <pre><code>DECLARE l_table_status VARCHAR2(8); l_index_status VARCHAR2(8); l_table_name VARCHAR2(30) := 'TEST'; l_index_name VARCHAR2(30) := 'IDX_TEST'; ex_no_metadata EXCEPTION; BEGIN BEGIN SELECT STATUS INTO l_table_status FROM USER_TABLES WHERE TABLE_NAME = l_table_name; EXCEPTION WHEN NO_DATA_FOUND THEN -- raise exception here with message saying -- "Table metadata does not exist." RAISE ex_no_metadata; END; BEGIN SELECT STATUS INTO l_index_status FROM USER_INDEXES WHERE INDEX_NAME = l_index_name; EXCEPTION WHEN NO_DATA_FOUND THEN -- raise exception here with message saying -- "Index metadata does not exist." RAISE ex_no_metadata; END; EXCEPTION WHEN ex_no_metadata THEN DBMS_OUTPUT.PUT_LINE('Exception will be handled by handle_no_metadata_exception(SQLERRM) procedure here.'); DBMS_OUTPUT.PUT_LINE(SQLERRM); END; / </code></pre> In reality, there are dozens of those sub-blocks. I'm wondering if there's a way to have a single user-defined exception for each of those sub-blocks to raise, but have it give a different message, instead of creating a separate user-defined exception for each sub-block. In .NET, it would be sort of like having a custom exception like this: <pre><code> public class ColorException : Exception { public ColorException(string message) : base(message) { } } </code></pre> And then, a method would have something like this: <pre><code> if (isRed) { throw new ColorException("Red is not allowed!"); } if (isBlack) { throw new ColorException("Black is not allowed!"); } if (isBlue) { throw new ColorException("Blue is not allowed!"); } </code></pre>

6,020,523

5

0

null

2011-05-16 16:32:55.703 UTC

37

2018-12-24 10:23:44.55 UTC

2015-06-02 11:11:55.713 UTC

null

2,296,199

null

467,055

null

1

86

oracle|exception|plsql|custom-exceptions

335,997

Yes. You just have to use the <code>RAISE_APPLICATION_ERROR</code> function. If you also want to name your exception, you'll need to use the <code>EXCEPTION_INIT</code> pragma in order to associate the error number to the named exception. Something like <pre><code>SQL> ed Wrote file afiedt.buf 1 declare 2 ex_custom EXCEPTION; 3 PRAGMA EXCEPTION_INIT( ex_custom, -20001 ); 4 begin 5 raise_application_error( -20001, 'This is a custom error' ); 6 exception 7 when ex_custom 8 then 9 dbms_output.put_line( sqlerrm ); 10* end; SQL> / ORA-20001: This is a custom error PL/SQL procedure successfully completed. </code></pre>

6,228,092

How can I compute a SHA-2 (ideally SHA 256 or SHA 512) hash in iOS?

The Security services API doesn't appear to allow me to compute a hash directly. There are plenty of public domain and liberally licensed versions available, but I'd rather use a system library implementation if possible. The data is accessible via NSData, or plain pointers. The cryptographic strength of the hash is important to me. SHA-256 is the minimum acceptable hash size.

6,228,385

6

0

null

2011-06-03 14:02:52.91 UTC

36

2018-07-17 20:44:20.797 UTC

null

233,201

null

1

59

objective-c|ios|security|hash|sha256

33,868

This is what I'm using for SHA1: <pre><code>#import <CommonCrypto/CommonDigest.h> + (NSData *)sha1:(NSData *)data { unsigned char hash[CC_SHA1_DIGEST_LENGTH]; if ( CC_SHA1([data bytes], [data length], hash) ) { NSData *sha1 = [NSData dataWithBytes:hash length:CC_SHA1_DIGEST_LENGTH]; return sha1; } return nil; } </code></pre> Replace <code>CC_SHA1</code> with <code>CC_SHA256</code> (or whichever you need), as well as <code>CC_SHA1_DIGEST_LENGTH</code> with <code>CC_SHA256_DIGEST_LENGTH</code>.

6,091,427

MYSQL into outfile "access denied" - but my user has "ALL" access.. and the folder is CHMOD 777

Any ideas? <pre><code>SELECT * INTO OUTFILE '/home/myacnt/docs/mysqlCSVtest.csv' FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '*' LINES TERMINATED BY '\n' FROM tbl_property WHERE managerGroupID = {$managerGroupID} </code></pre> Error: <pre><code>Access denied for user 'asdfsdf'@'localhost' (using password: YES) </code></pre>

6,091,447

6

2

null

2011-05-22 23:07:51.18 UTC

24

2020-05-10 14:45:20.38 UTC

2011-05-22 23:22:17.837 UTC

null

135,152

null

646,456

null

1

86

mysql|mysql-error-1045|into-outfile

185,439

Try executing this SQL command: <pre><code>> grant all privileges on YOUR_DATABASE.* to 'asdfsdf'@'localhost' identified by 'your_password'; > flush privileges; </code></pre> It seems that you are having issues with connecting to the database and not writing to the folder you’re mentioning. Also, make sure you have granted <code>FILE</code> to user <code>'asdfsdf'@'localhost'</code>. <pre><code>> GRANT FILE ON *.* TO 'asdfsdf'@'localhost'; </code></pre>

6,236,251

Android: get facebook friends list

I am using the <a href="https://github.com/facebook/facebook-android-sdk/" rel="nofollow">Facebook SDK</a> to post messages on walls. Now I need to fetch the Facebook friends list. Can anybody help me with this? -- Edit -- <pre><code>try { Facebook mFacebook = new Facebook(Constants.FB_APP_ID); AsyncFacebookRunner mAsyncRunner = new AsyncFacebookRunner(mFacebook); Bundle bundle = new Bundle(); bundle.putString("fields", "birthday"); mFacebook.request("me/friends", bundle); } catch(Exception e){ Log.e(Constants.LOGTAG, " " + CLASSTAG + " Exception = "+e.getMessage()); } </code></pre> When I execute my <code>activity</code>, I'm not seeing anything, but in <code>LogCat</code> there is a debug message like: <pre><code>06-04 17:43:13.863: DEBUG/Facebook-Util(409): GET URL: https://graph.facebook.com/me/friends?format=json&fields=birthday </code></pre> And when I tried to access this url directly from the browser, I'm getting the following error response: <pre><code>{ error: { type: "OAuthException" message: "An active access token must be used to query information about the current user." } } </code></pre>

6,236,755

8

2

null

2011-06-04 10:42:01.87 UTC

7

2015-10-16 09:05:36.4 UTC

2014-04-11 06:37:04.913 UTC

null

2,463,160

null

540,638

null

1

13

android|facebook

42,510

You are about half way there. You've sent the request, but you haven't defined anything to receive the response with your results. You can extend <code>BaseRequestListener</code> class and implement its <code>onComplete</code> method to do that. Something like this: <pre><code>public class FriendListRequestListener extends BaseRequestListener { public void onComplete(final String response) { _error = null; try { JSONObject json = Util.parseJson(response); final JSONArray friends = json.getJSONArray("data"); FacebookActivity.this.runOnUiThread(new Runnable() { public void run() { // Do stuff here with your friends array, // which is an array of JSONObjects. } }); } catch (JSONException e) { _error = "JSON Error in response"; } catch (FacebookError e) { _error = "Facebook Error: " + e.getMessage(); } if (_error != null) { FacebookActivity.this.runOnUiThread(new Runnable() { public void run() { Toast.makeText(getApplicationContext(), "Error occurred: " + _error, Toast.LENGTH_LONG).show(); } }); } } } </code></pre> Then in your request you can specify the request listener to use for receiving the response from the request, like this: <pre><code>mFacebook.request("me/friends", bundle, new FriendListRequestListener()); </code></pre>

49,741,379

DialogFragment Class Deprecated in Android P

The Android Documentation gives the following warning. <blockquote> This class was deprecated in API level P. Use the Support Library DialogFragment for consistent behavior across all devices and access to Lifecycle. </blockquote> Does this simply mean that the only change for me as a developer is to import <code>android.support.v4.app.DialogFragment</code> instead of the old <code>android.app.DialogFragment</code>?

49,742,389

1

null

2018-04-09 20:40:45.53 UTC

3

2018-12-14 11:07:57.94 UTC

2018-05-07 10:30:07.177 UTC

null

9,298,629

null

8,700,524

null

1

32

android|android-fragments|android-alertdialog|android-9.0-pie

20,695

Google is encouraging all developers to shift from the ordinary DialogFragment to the support version of the same class, you can still use the deprecated version of course but if Google recommends the support version, why wouldn't you? Simply change your import statement from <code>android.app.DialogFragment</code> to <code>android.support.v4.app.DialogFragment</code>. Also, consider changing all the imports if you are using the deprecated version of normal fragments. UPDATE If you are using the brand new AndroidX library instead of the old support library change it to <code>androidx.fragment.app.DialogFragment</code> but pay attention about how you are using the DialogFragment in your code because you have to migrate also to the new <code>androidx.fragment.app.FragmentActivity</code>.

25,372,911

python/pip error on osx

I've recently purchased a new hard drive and installed a clean copy of OS X Mavericks. I installed python using homebrew and i need to create a python virtual environment. But when ever i try to run any command using pip, I get this error. I haven't been able to find a solution online for this problem. Any reference would be appreciated. Here is the error I'm getting. <pre><code>ERROR:root:code for hash md5 was not found. Traceback (most recent call last): File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 139, in <module> globals()[__func_name] = __get_hash(__func_name) File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 91, in __get_builtin_constructor raise ValueError('unsupported hash type ' + name) ValueError: unsupported hash type md5 ERROR:root:code for hash sha1 was not found. Traceback (most recent call last): File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 139, in <module> globals()[__func_name] = __get_hash(__func_name) File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 91, in __get_builtin_constructor raise ValueError('unsupported hash type ' + name) ValueError: unsupported hash type sha1 ERROR:root:code for hash sha224 was not found. Traceback (most recent call last): File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 139, in <module> globals()[__func_name] = __get_hash(__func_name) File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 91, in __get_builtin_constructor raise ValueError('unsupported hash type ' + name) ValueError: unsupported hash type sha224 ERROR:root:code for hash sha256 was not found. Traceback (most recent call last): File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 139, in <module> globals()[__func_name] = __get_hash(__func_name) File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 91, in __get_builtin_constructor raise ValueError('unsupported hash type ' + name) ValueError: unsupported hash type sha256 ERROR:root:code for hash sha384 was not found. Traceback (most recent call last): File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 139, in <module> globals()[__func_name] = __get_hash(__func_name) File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 91, in __get_builtin_constructor raise ValueError('unsupported hash type ' + name) ValueError: unsupported hash type sha384 ERROR:root:code for hash sha512 was not found. Traceback (most recent call last): File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 139, in <module> globals()[__func_name] = __get_hash(__func_name) File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 91, in __get_builtin_constructor raise ValueError('unsupported hash type ' + name) ValueError: unsupported hash type sha512 Traceback (most recent call last): File "/usr/local/bin/pip", line 9, in <module> load_entry_point('pip==1.5.6', 'console_scripts', 'pip')() File "build/bdist.macosx-10.9-x86_64/egg/pkg_resources.py", line 356, in load_entry_point File "build/bdist.macosx-10.9-x86_64/egg/pkg_resources.py", line 2439, in load_entry_point File "build/bdist.macosx-10.9-x86_64/egg/pkg_resources.py", line 2155, in load File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/__init__.py", line 10, in <module> from pip.util import get_installed_distributions, get_prog File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/util.py", line 18, in <module> from pip._vendor.distlib import version File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/_vendor/distlib/version.py", line 14, in <module> from .compat import string_types File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/_vendor/distlib/compat.py", line 31, in <module> from urllib2 import (Request, urlopen, URLError, HTTPError, ImportError: cannot import name HTTPSHandler </code></pre> If you need any extra information from me let me know, this is my first time posting a question here. Thanks.

25,373,020

4

1

null

2014-08-18 22:17:15.087 UTC

14

2019-11-27 18:41:04.587 UTC

null

3,954,316

null

1

24

python|macos

24,738

Ok I found out <a href="https://github.com/Homebrew/legacy-homebrew/issues/22816#issuecomment-39017095" rel="noreferrer">online</a> that these errors are related to openssl. But i already had openssl installed. A little more research and I tried the following and it solved the issue for me. Here's my solution in case you get the same error. <pre><code>brew install openssl brew link openssl --force brew uninstall python brew install python --with-brewed-openssl </code></pre> Hope that helps.

24,566,692

Filezilla FTP Server Fails to Retrieve Directory Listing

I'm running Filezilla Server 0.9.45 beta to manage my server remotely. After setting it up, I tested connecting to it using the IP <code>127.0.0.1</code>, and it worked successfully. However, to connect to the server remotely, I port forwarded to port 21, and tried to connect using my computer's IP. <pre><code>Status: Connecting to [My IP]:21... Status: Connection established, waiting for welcome message... Response: 220 Powered By FileZilla Server version 0.9.45 beta Command: USER hussain khalil Response: 331 Password required for user Command: PASS ********* Response: 230 Logged on Status: Connected Status: Retrieving directory listing... Command: CWD / Response: 250 CWD successful. "/" is current directory. Command: PWD Response: 257 "/" is current directory. Command: TYPE I Response: 200 Type set to I Command: PORT 192,168,0,13,205,63 Response: 200 Port command successful Command: MLSD Response: 150 Opening data channel for directory listing of "/" Response: 425 Can't open data connection for transfer of "/" Error: Failed to retrieve directory listing </code></pre> This continues to work locally, but not when connecting remotely... How can I fix this?

24,570,363

22

1

null

2014-07-04 04:25:35 UTC

12

2021-11-13 07:21:13.513 UTC

null

3,571,248

null

1

101

ftp|filezilla

352,874

When you send the port command to your server, you are asking the server to connect to you (on the remote network). If the remote network also has a NAT router, and you have not port-forwarded the port you are sending with your PORT command, the server will not be able reach you. The most common solution would be to send the PASV command to the server instead of the PORT command. The PASV command will ask the server to create a listening socket and accept a connection from the remote machine to establish the data connection. For the PASV command to work, you will also need to port-forward a range of ports for the passive data connections. The passive connection ports (which need to be forwarded) should be listed in the FileZilla documentation.

27,712,472

Choosing between SimHash and MinHash for a production system

I'm familiar with the LSH (Locality Sensitive Hashing) techniques of SimHash and MinHash. SimHash uses cosine similarity over real-valued data. MinHash calculates resemblance similarity over binary vectors. But I can't decide which one would be better to use. I am creating a backend system for a website to find near duplicates of semi-structured text data. For example, each record will have a title, location, and a brief text description (<500 words). Specific language implementation aside, which algorithm would be best for a greenfield production system?

46,415,603

2

null

2014-12-30 20:59:04.21 UTC

10

2019-05-23 15:24:53.027 UTC

null

1,987,762

null

1,987,762

null

1

16

minhash|simhash

11,339

Simhash is faster (very fast) and typically requires less storage, but imposes a strict limitation on how dissimilar two documents can be and still be detected as duplicates. If you are using a 64-bit simhash (a common choice), and depending on how many permuted tables you are capable of storing, you might be limited to hamming distances of as low as 3 or possibly as high as 6 or 7. Those are small hamming distances! You'll be limited to detecting documents that are mostly identical, and even then you may need to do some careful tuning of what features you choose to go into the simhash and what weightings you give to them. The generation of simhashes is patented by google, though in practice they seem to allow at least non-commercial use. Minhash uses more memory, since you'd be typically storing 50-400 hashes per document, and it's not as CPU-efficient as simhash, but it allows you to find quite distant similarities, e.g. as low as 5% estimated similarity, if you want. It's also a bit easier to understand than simhash, particularly in terms of how the tables work. It's quite straightforward to implement, typically using shingling, and doesn't need a lot of tuning to get good results. It's not (to my knowledge) patented. If you're dealing with big data, the most CPU-intensive part of the minhash approach will likely be after you've generated the minhashes for your document, when you're hunting through your table to find other documents that share some of its hashes. There may be tens or hundreds of thousands of documents that share at least one hash with it, and you've got to weed through all of these to find those few that share e.g. a minimum of half its hashes. Simhash is a lot quicker here. As Otmar points out in his comment below, there are optimizations of minhash that allow you to achieve the same precision on your similarity estimates with fewer hashes per document. This can substantially reduce the amount of weeding you have to do. Edit: I have now tried <a href="https://arxiv.org/pdf/1706.05698.pdf" rel="noreferrer">superminhash</a>. It's fairly fast, though my implementation of minhash <a href="https://stackoverflow.com/questions/19701052/how-many-hash-functions-are-required-in-a-minhash-algorithm">using a single hash function plus bit-transformations to produce all the other hashes</a> was faster for my purposes. It offers more accurate jaccard estimates, about 15% better under some situations I tested (though almost no difference under others). This should mean you need about a third fewer hashes to achieve the same accuracy. Storing fewer hashes in your table means less "weeding" is needed to identify near duplicates, which delivers a significant speed-up. I'm not aware of any patent on superminhash. Thanks Otmar!

21,609,012

Disable readonly to text box onclicking the button

I have used "readonly" attribute to the textbox which makes the textbox non editable and may i know how to disable the readonly attribute on clicking the button. can we do this by using any script ? <pre class="lang-html prettyprint-override"><code><input type="text" name="" value="" readonly="readonly"/> <input type="submit" name="" value="update" onclick="" /> </code></pre>

21,609,128

3

1

null

2014-02-06 16:50:20.143 UTC

2

2020-11-17 18:06:53.183 UTC

null

806,169

null

2,823,321

null

1

17

javascript|html

68,959

You can do two things: <ul> <li>Remove the <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Input#attr-readonly" rel="noreferrer"><code>readonly</code></a> (case insensitive) attribute, using <a href="https://developer.mozilla.org/en-US/docs/Web/API/Element.removeAttribute" rel="noreferrer"><code>removeAttribute</code></a></li> <li>Set the <a href="https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement#Properties" rel="noreferrer"><code>readOnly</code></a> (case sensitive) property to <code>false</code></li> </ul> HTML: <pre><code><input id="myInput" type="text" readonly="readonly" /> <input id="myButton" type="submit" value="update" /> </code></pre> JS (option 1): [<a href="http://jsfiddle.net/343Rb/" rel="noreferrer">Demo</a>] <pre><code>document.getElementById('myButton').onclick = function() { document.getElementById('myInput').removeAttribute('readonly'); }; </code></pre> JS (option 2): [<a href="http://jsfiddle.net/343Rb/1/" rel="noreferrer">Demo</a>] <pre><code>document.getElementById('myButton').onclick = function() { document.getElementById('myInput').readOnly = false; }; </code></pre>

21,569,718

How do I exit a Rust program early from outside the main function?

I am in the process of writing a <code>bash</code> clone in Rust. I need to have my program exit when the user types <code>exit</code>. In previous iterations of my program, before I added more complicated features, I used <code>return</code> to get out of the loop that was prompting the user for input. This logic is now in a function, because of the way I am implementing built in shell functions, so when I <code>return</code> it just jumps out of the function back into the control loop, instead of short-circuiting the control loop and ending the program. I realize that I could probably return a boolean when the user types <code>exit</code> and exit the loop, but I would like to at least know if Rust has a way to terminate programs early, similar to Java's <code>System.exit()</code>, as this is useful for certain types of programs.

21,570,851

2

1

null

2014-02-05 06:00:20.17 UTC

4

2019-02-15 09:36:38.397 UTC

2018-05-31 15:42:01.123 UTC

null

155,423

null

2,448,605

null

1

52

system|rust

30,162

<h3>Rust 1.0 stable</h3> <a href="http://doc.rust-lang.org/std/process/fn.exit.html" rel="noreferrer"><code>std::process::exit()</code></a> does exactly that - it terminates the program with the specified exit code: <pre><code>use std::process; fn main() { for i in 0..10 { if i == 5 { process::exit(1); } println!("{}", i); } } </code></pre> This function causes the program to terminate immediately, without unwinding and running destructors, so it should be used sparingly. <h3>Alternative (not recommended) solution</h3> You can use C API directly. Add <code>libc = "0.2"</code> to <code>Cargo.toml</code>, and: <pre><code>fn main() { for i in 0..10 { if i == 5 { unsafe { libc::exit(1); } } println!("{}", i); } } </code></pre> Calling C functions cannot be verified by the Rust compiler, so this requires the <code>unsafe</code> block. Resources used by the program will not be freed properly. This may cause problems such as hanging sockets. As far as I understand, the proper way to exit from the program is to terminate all threads somehow, then the process will exit automatically.

32,642,417

PHP date time greater than today

please help what's wrong with my code? It always returns that today's date is greater than '01/02/2016' wherein 2016 is greater than in 2015. <pre><code><?php $date_now = date("m/d/Y"); $date = date_create("01/02/2016"); $date_convert = date_format($date, "m/d/Y"); if ($date_now > $date_convert) { echo 'greater than'; } else { echo 'Less than'; } </code></pre> P.S: 01/02/2016 is coming from the database.

32,642,436

3

1

null

2015-09-18 01:20:53.093 UTC

18

2022-07-01 07:59:45.86 UTC

2020-06-02 14:34:16.077 UTC

null

5,211,514

null

3,363,230

null

1

58

php|date

174,806

You are not comparing dates. You are comparing strings. In the world of string comparisons, <code>09/17/2015</code> > <code>01/02/2016</code> because <code>09</code> > <code>01</code>. You need to either put your date in a comparable string format or compare <code>DateTime</code> objects which are comparable. <pre><code><?php $date_now = date("Y-m-d"); // this format is string comparable if ($date_now > '2016-01-02') { echo 'greater than'; }else{ echo 'Less than'; } </code></pre> <a href="https://3v4l.org/LU115" rel="noreferrer">Demo</a> Or <pre><code><?php $date_now = new DateTime(); $date2 = new DateTime("01/02/2016"); if ($date_now > $date2) { echo 'greater than'; }else{ echo 'Less than'; } </code></pre> <a href="https://3v4l.org/5rQVP" rel="noreferrer">Demo</a>

9,623,769

ORA-04045: errors during recompilation/revalidation

I just suddenly started getting this error when trying to query the table AVC. <pre><code>ORA-04045: errors during recompilation/revalidation of PUBLIC.AVC ORA-04098: trigger 'TTMS.ALTERED_TTMSDB_TABS_TRIGGER' is invalid and failed re-validation </code></pre> <code>select * from avc</code> doesnt work but <code>select * from exfc.avc</code> does work. Can anyone tell me what is going on?

9,623,890

2

0

null

2012-03-08 19:41:17.87 UTC

null

2019-09-12 12:42:22.027 UTC

2016-11-17 21:03:12.473 UTC

null

393,243

null

802,331

null

1

3

oracle

45,983

Presumably there is not an object in your schema named <code>AVC</code>. When you reference <code>AVC</code> without a schema qualifier, it is therefore accessing the <code>PUBLIC</code> object with that name. To find out what kind of object that is, <code>SELECT object_type FROM all_objects WHERE object_name='AVC' AND owner='PUBLIC'</code>. Whatever it is, querying it is for some reason causing a trigger to fire. Maybe this is some sort of auditing function. But currently the trigger is invalid. This could mean that someone modified the trigger itself but made an error; or it could mean that someone dropped or modified some other object that the trigger depends on, in such a way that the trigger code is no longer valid. So, whoever's responsible for that trigger needs to find out what error is occurring in its compilation and resolve it. When you explicitly query <code>EXFC.AVC</code>, you are bypassing the <code>PUBLIC</code> object and going directly to some underlying object, probably an actual table. It seems very odd that you would have access to this, since the whole point of routing access through a public synonym is usually to prevent direct access to the object. And if, in fact, the purpose of the trigger is to audit accesses to the table, then allowing you to bypass it entirely is a pretty big design flaw.

9,283,188

How to efficiently find CGRects for visible words in UITextView?

My goal is to mark all visible misspelled words in an UITextView. The inefficient algorithm is to use the spell checker to find all ranges of misspelled words in the text, convert them to UITextRange objects using positionFromPosition:inDirection:offset etc, then get the graphics rects using the UITextInput method firstRectFromRange. Thus all the text -> misspelled words-> NSRange collection -> UITextRange collection -> CGRect collection -> evaluate for visibility, draw visible ones The problem is that this requires that all the text is checked, and all misspelled words are converted to graphics rects. Thus, I imagine the way to go is to somehow find out what parts of the underlying .text in the UITextView that is visible at the moment. Thus for range of text visible -> misspelled words-> NSRange collection -> UITextRange collection -> CGRect collection -> evaluate for visibility, draw visible ones The code in <a href="https://stackoverflow.com/questions/6067803/ios-how-to-find-what-is-the-visible-range-of-text-in-uitextview">ios - how to find what is the visible range of text in UITextView?</a> might work as a way to bound what parts of the text to check, but still requires that all text is measured, which I imagine could be quite costly. Any suggestions?

9,283,311

2

0

null

2012-02-14 19:43:50.417 UTC

9

2018-05-28 05:07:10.38 UTC

2017-05-23 12:08:47.533 UTC

null

-1

null

787,610

null

1

10

ios

4,665

Since <code>UITextView</code> is a subclass of <code>UIScrollView</code>, its <code>bounds</code> property reflects the visible part of its coordinate system. So something like this should work: <pre><code>- (NSRange)visibleRangeOfTextView:(UITextView *)textView { CGRect bounds = textView.bounds; UITextPosition *start = [textView characterRangeAtPoint:bounds.origin].start; UITextPosition *end = [textView characterRangeAtPoint:CGPointMake(CGRectGetMaxX(bounds), CGRectGetMaxY(bounds))].end; return NSMakeRange([textView offsetFromPosition:textView.beginningOfDocument toPosition:start], [textView offsetFromPosition:start toPosition:end]); } </code></pre> This assumes a top-to-bottom, left-to-right text layout. If you want to make it work for other layout directions, you will have to work harder. :)

9,127,301

Get entity name from class object

I have the following code: <pre><code>namespace Acme\StoreBundle\Entity; use Doctrine\ORM\Mapping as ORM; /** * Acme\StoreBundle\Entity\User * * @ORM\Table(name="users") * @ORM\Entity() */ class User { ... } $user = new User(); </code></pre> Does anybody know how I can now get the entity name (<code>AcmeStoreBundle:User</code>) from the <code>User</code> object?

14,229,984

4

0

null

2012-02-03 10:42:07.563 UTC

0

2020-04-16 19:38:49.89 UTC

2013-11-14 19:58:34.73 UTC

user212218

null

1,028,177

null

1

19

symfony|doctrine-orm

43,001

This should always work (no return of Proxy class): <pre><code>$em = $this->container->get('doctrine')->getEntityManager(); $className = $em->getClassMetadata(get_class($object))->getName(); </code></pre> As <code>getClassMetadata</code> is deprecated, you can now use <code>getMetadataFor</code> <pre><code>$entityName = $this->em->getMetadataFactory()->getMetadataFor(get_class($object))->getName(); </code></pre>

9,226,263

Moving Onto The Next UITextField When 'Next' Is Tapped

I have an iPad application which has a sign up form within it. The form is very basic and contains only two UITextFields which are for Name & Email address. The first TextField is for the candidates Name, When they enter their name in and press 'Next' on the keyboard I want this to automatically move to the next Email Address TextField to editing. Any idea how I can set the next button the keyboard to jump to the next keyboard? Thanks

9,226,363

7

0

null

2012-02-10 10:26:33.117 UTC

12

2018-11-14 21:08:59.787 UTC

null

659,583

null

1

38

objective-c|xcode|ipad|ios4|uitextfield

30,851

You need to make your view controller the UITextField delegate, and implement the UITextField delegate method: <pre><code>- (BOOL)textFieldShouldReturn:(UITextField *)textField { if (textField == nameField) { [textField resignFirstResponder]; [emailField becomeFirstResponder]; } else if (textField == emailField) { // here you can define what happens // when user presses return on the email field } return YES; } </code></pre> Swift version: <pre><code>func textFieldShouldReturn(textField: UITextField) -> Bool { if textField == nameField { textField.resignFirstResponder() emailField.becomeFirstResponder() } else if textField == emailField { // here you can define what happens // when user presses return on the email field } return true } </code></pre> You may also want to scroll your view for the emailField to become visible. If your view controller is an instance of UITableViewController, this should happen automatically. If not, you should read <a href="https://developer.apple.com/library/ios/#documentation/StringsTextFonts/Conceptual/TextAndWebiPhoneOS/KeyboardManagement/KeyboardManagement.html" rel="noreferrer">this Apple document</a>, especially Moving Content That Is Located Under the Keyboard part.

34,114,679

Convert a React.element to a JSX string

I am trying to build a component which, <ol> <li>Takes children and </li> <li>Renders the children in the DOM and also,</li> <li>Shows the children DOM in a <code>pre</code> for documentation sake</li> </ol> One solution is to pass the JSX as a separate <code>prop</code> as well. This makes it repetitive since I am already able to access it through <code>this.props.children</code>. Ideally, I just need to somehow convert the <code>children</code> prop as a <code>string</code> so that I can render it in a <code>pre</code> to show that "this code produces this result". This is what I have so far <pre><code>class DocumentationSection extends React.Component{ render(){ return <div className="section"> <h1 className="section__title">{heading || ""}</h1> <div className="section__body"> {this.props.children}</div> <pre className="section__src"> //Change this to produce a JSX string from the elements {this.props.children} </pre> </div>; } } </code></pre> How can I get the a jsx string in the format <code>'<Div className='myDiv'>...</Div></code> when I render DocumentationSection as <pre><code><DocumentationSection heading='Heading 1'> <Div className='myDiv'>...</Div> </DocumentationSection> </code></pre> Thanks. Edit: I tried toString, it dint work, gave [object Object]

34,114,771

4

1

null

2015-12-06 06:19:31.173 UTC

7

2021-06-23 19:17:45.887 UTC

null

2,621,400

null

1

35

javascript|reactjs

79,566

If you want the HTML representation of a React element you can use <code>#renderToString</code> or <code>#renderToStaticMarkup</code>. <pre><code>ReactDomServer.renderToString(<div>p</div>); ReactDomServer.renderToStaticMarkup(<div>p</div>); </code></pre> will produce <pre><code><div data-reactid=".1" data-react-checksum="-1666119235">p</div> </code></pre> and <pre><code><div>p</div> </code></pre> respectively. You will however not be able to render the parent as a string from within itself. If you need the parent too then from where you render the parent pass a <code>renderToString</code> version of it as props to itself.

34,075,486

How to list the regions in an HBase table through the shell?

I would like to get the same information about the regions of a table that appear in the web UI (i.e. region name, region server, start/end key, locality), but through the hbase shell. (The UI is flaky/slow, and furthermore I want to process this information as part of a script.) After much googling, I can't find out how, and this surprises me immensely. version is 1.0.0.-cdh5.4.0

34,082,230

5

2

null

2015-12-03 20:24:48.317 UTC

13

2020-08-13 11:03:44.77 UTC

null

19,269

null

1

21

hbase

33,119

To get the region info about the table, you need to scan <code>hbase:meta</code> table. <pre><code>scan 'hbase:meta',{FILTER=>"PrefixFilter('table_name')"} </code></pre> This command will give details of all the regions. Row key will have region name and there will be four column qualifiers. You may need following two column qualifiers: <code>info:regioninfo</code> - This qualifier contains STARTKEY and ENDKEY. <code>info:server</code> - This qualifier contains region server details

10,538,718

jQuery Mobile pageinit/pagecreate not firing

I have 5 pages - for ease lets say: <ul> <li>one.html</li> <li>two.html</li> <li>three.html</li> <li>four.html</li> <li>five.html</li> </ul> When I load each individual page, both <code>pageinit</code> and <code>pagecreate</code> are firing correctly. The Problem: When I go from one.html to two.html, <code>pageinit</code> and <code>pagecreate</code> both fire, BUT when I go back to one.html (from two.html), <code>pageinit</code> and <code>pagecreate</code> DO NOT fire. Why is this and how can I always fire <code>pageinit</code> and <code>pagecreate</code> on page load, as well as navigating through each page? Update: For each page I have: <pre><code><div data-role="page" id="page-name"> // content </div> </code></pre> To test the order at when things are firing I do: <pre><code>$(document).on('pagecreate','[data-role=page]', function(){ console.log('PAGECREATE'); }); $(document).on('pageinit','[data-role=page]', function(){ console.log('PAGEINIT'); }); $(document).on('pagebeforeshow','[data-role=page]', function(){ console.log('PAGEBEFORESHOW'); }); $(document).on('pageshow','[data-role=page]', function(){ console.log('PAGESHOW'); }); </code></pre> How do I use the pagechange to always call the <code>pageinit</code> and <code>pagecreate</code>

10,542,821

7

1

null

2012-05-10 16:48:04.457 UTC

9

2014-06-25 03:40:32.177 UTC

2012-05-10 17:20:44.98 UTC

null

884,951

null

884,951

null

1

18

jquery|jquery-mobile

26,988

You're checking for the wrong events, pageinit and pageshow are what you should be concerned about. pageinit fires everytime a page is loaded for the first time, jQM caches pages in the DOM/memory so when you navigate back from two.html to one.html, pageinit won't fire (it's already initialized) pageshow fires everytime a page is shown, this is what you need to be looking for when you navigate back from two.html to one.html Together you can pull off a lot of clean code, use pageinit for initializing, configuration etc and update your DOM to the initial state. If you have dynamic data on the page that may change between views, handle it in pageshow Here's a good design for larger websites that we use in a production environment: <ol> <li>bind a live event to all pages/dialogs pageinit and pageshow events in some include that is on every page: <code>$(document).on('pageinit pageshow', 'div:jqmData(role="page"), div:jqmData(role="dialog")', function(event){</code></li> <li>I reference each page with a name: <code><div data-role="page" data-mypage="employeelist"></code> In this live event you can basically have a switch statement for each page "name", and then check event.type for pageinit/pageshow or both and put your code there, then every time a page is created/shown this event will be fired, it knows what page triggered it and then calls the corresponding code</li> <li>Now no matter what entry point a user lands on your site, all the handlers for all the pages are loaded. As you may already know, when you navigate to a page, it only pulls in <code><script/></code> within the div[data-role="page"] - ignoring any JS in the <code><head/></code>, placing separate JS on each page is a mess and should be avoided in any large site I believe</li> <li>Try not to use blanket selectors in your jQuery, e.g. <code>$('div.myClass')</code> since this will search all of your DOM which may have more than one jQM page in it. Luckily in the live event handler for pageinit/pageshow mentioned above, <code>this</code> refers to the current page. So do all DOM searches within it, e.g. <code>$(this).find('div.myClass')</code> this ensures you are only grabbing elements within the current page. (of course this isn't a concern for ids). Note in the pageshow event you can also use <code>$.mobile.activePage</code>, but this isn't available in the pageinit, so I don't use it for consistency</li> </ol> I eventually had too much code, so I built a handler object where each page's js is included in a separate js file and can register handlers with the live event The drawback is that all your js for your entire site is loaded on the first page the user reaches, but minified even a large site is smaller than jQuery or jQM so this shouldn't be a concern. But if your site really is large I suppose you could look into RequireJS. An advantage is you are no longer loading all your JS for each page through AJAX each time the user navigates to a new page. If all your JS is available on entry, you can now put debugger statements and debug much more easily!

10,398,543

Play framework 2.0 continuous integration setup

I am looking for ideas for a Play 2.0 continuous integration setup. It would contain typical jobs like build after a git push, nightly builds with deployment to a test Heroku instance etc. Also code quality and test coverage metrics generation would be handy. At the moment the stack looks like Play 2.0 with Java but that might change to Scala. For "traditional" Java web app I would use Hudson/Jenkins. I found a <a href="http://wiki.hudson-ci.org/display/HUDSON/play-plugin" rel="noreferrer">Hudson plugin for Play</a> but it doesn't seem to support Play 2.0. Is Hudson suitable tool here in general or what is your setup for Play 2.0 applications?

10,409,020

4

1

null

2012-05-01 13:43:05.227 UTC

13

2013-05-31 09:56:59.993 UTC

2013-05-28 18:49:59.737 UTC

null

98,632

null

28,841

null

1

26

testing|continuous-integration|hudson|jenkins|playframework-2.0

10,363

Play 2.0's build tool is just a thin wrapper around <a href="https://github.com/harrah/xsbt/wiki">SBT</a>. You should be able to use Hudson's <a href="http://wiki.hudson-ci.org/display/HUDSON/sbt+plugin">sbt plugin</a> to execute SBT build commands that are the equivalent of the Play commands you would execute from the console. We execute the following under Bamboo for our builds: <pre><code>SBT_OPTS="-Dsbt.log.noformat=true" sbt clean compile test </code></pre> (The SBT_OPTS variable turns off the colour formatting, making test output legible in log files.)

10,467,024

How do I create my own NLTK text from a text file?

I'm a Literature grad student, and I've been going through the O'Reilly book in Natural Language Processing (nltk.org/book). It looks incredibly useful. I've played around with all the example texts and example tasks in Chapter 1, like concordances. I now know how many times Moby Dick uses the word "whale." The problem is, I can't figure out how to do these calculations on one of my own texts. I've found information on how to create my own corpora (Ch. 2 of the O'Reilly book), but I don't think that's exactly what I want to do. In other words, I want to be able to do <pre><code>import nltk text1.concordance('yellow') </code></pre> and get the places where the word 'yellow' is used in my text. At the moment I can do this with the example texts, but not my own. I'm very new to python and programming, and so this stuff is very exciting, but very confusing.

10,467,054

3

1

null

2012-05-06 00:13:23.22 UTC

16

2020-09-07 09:35:17.063 UTC

null

584,121

null

1

37

python|nltk

28,884

Found the answer myself. That's embarrassing. Or awesome. From Ch. 3: <pre><code>f=open('my-file.txt','rU') raw=f.read() tokens = nltk.word_tokenize(raw) text = nltk.Text(tokens) </code></pre> Does the trick.

7,451,299

How do I preserve the remote filename when Downloading a file using curl

<blockquote> Possible Duplicate: <a href="https://stackoverflow.com/questions/2698552/how-do-i-save-a-file-using-the-response-header-filename-with-curl">How do I save a file using the response header filename with cURL</a> </blockquote> I need to download many thousands of images in the format <a href="http://oregondigital.org/cgi-bin/showfile.exe?CISOROOT=/baseball&CISOPTR=0" rel="noreferrer">http://oregondigital.org/cgi-bin/showfile.exe?CISOROOT=/baseball&CISOPTR=0</a> If you paste that link in a browser, it tries to download a file named 1.jp2 I want to use curl to do the same. However, when I run curl -I '<a href="http://oregondigital.org/cgi-bin/showfile.exe?CISOROOT=/baseball&CISOPTR=0" rel="noreferrer">http://oregondigital.org/cgi-bin/showfile.exe?CISOROOT=/baseball&CISOPTR=0</a>' the filename is reported as 404.txt which you can download and see that it is actually the file I want. I can't use the -O option because the name assigned to the file is no good, and I have technical reasons for needing the actual name used on the system. How do I get curl to download the same file I have no trouble retrieving in my browser? Thanks.

7,451,779

2

1

null

2011-09-16 23:19:51.35 UTC

29

2018-03-29 18:55:15.817 UTC

2017-05-23 11:54:59.723 UTC

null

-1

null

493,144

null

1

115

shell|scripting|curl

57,595

The solution is to use <code>-O -J</code> <blockquote> <pre><code>-O, --remote-name Write output to a file named as the remote file -J, --remote-header-name Use the header-provided filename </code></pre> </blockquote> So... <pre><code>curl -O -J 'http://oregondigital.org/cgi-bin/showfile.exe?CISOROOT=/baseball&CISOPTR=0' </code></pre> I had to upgrade my CURL. I had v 7.19 which doesn't support -J but 7.22 (which is the latest) does.

31,415,270

Parse JSON and show data in Angular

I have a trouble with displaying JSON data in Angular. I successfully send data from backend to frontend (Angular), but I cannot display them. I tried to simulate a similar situation on <a href="http://jsfiddle.net/29y61wtg/2/" rel="noreferrer">JSFiddle</a>, although I already have prepared data from backend <img src="https://i.stack.imgur.com/tMN37.png" alt="following format"> get/send data -> Backend side: <pre><code>//push data to Redis var messages= JSON.stringify( [ { "name": "Msg1", "desc": "desc Msg1" }, { "name": "Msg2", "desc": "desc Msg2" }, { "name": "Msg3", "desc": "desc Msg3" }, { "name": "Msg4", "desc": "desc Msg4" } ]); redisClient.lpush('list', messages, function (err, response) { console.log(response); }); //get from redis and send to frontend app.get('/messages', function(req, res){ // Query your redis dataset here redisClient.lrange('list', 0, -1, function(err, messages) { console.log(messages); // Handle errors if they occur if(err) res.status(500).end(); // You could send a string res.send(messages); // or json // res.json({ data: reply.toString() }); }); }); </code></pre> get data -> frontend (Angular) <pre><code>angular.module('app') .controller('MainCtrl', ['$scope', '$http', function ($scope, $http) { 'use strict'; getFromServer(); function getFromServer(){ $http.get('/messages') .success(function(res){ $scope.messages= res; console.log(res); }); } }]) </code></pre> HTML part with ng-repeat directive: <pre><code><div ng-app="app" ng-controller="MainCtrl" class="list-group"> <div class="list-group-item" ng-repeat="item in messages"> <h4 class="list-group-item-heading">{{item.name}}</h4> {{item.desc}} <div> </div> </code></pre> Would anyone know what the problem is?

31,415,414

1

3

null

2015-07-14 19:08:27.397 UTC

2

2015-07-14 19:28:14.51 UTC

null

3,265,921

null

1

13

json|angularjs|node.js|express

113,199

As far as I can see, you're storing your Object as JSON, but you never parse it. Therefore using <pre><code>$scope.messages = JSON.parse(res); </code></pre> instead of <pre><code>$scope.messages = res; </code></pre> should fix your problem. Here is a working JSFiddle version of yours: <a href="https://jsfiddle.net/29y61wtg/5/" rel="noreferrer">https://jsfiddle.net/29y61wtg/5/</a> Note, that this doesn't include a $http call, if you're still having problems after using $http, tell me in the comments.