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

18,839,769

The max product of consecutive elements in an array

I was asked this algorithm question during my onsite interview. Since I was not asked to sign NDA, I post it here for an answer. Given an array of REAL numbers that does not contain 0, find the consecutive elements that yield max product. The algorithm should run in linear time I have considered the following approach: Use two arrays. First one is to use DP idea to record the current max absolute value product, the second array to record the number of negative elements met so far. The final result should be the largest max absolute value and the number of negative numbers be even. I thought my method will work, but was interrupted during coding saying it will not work. Please let me know what is missing in the above approach.

18,840,236

9

12

null

2013-09-17 01:10:24.89 UTC

21

2021-11-25 15:34:45.127 UTC

2013-10-14 19:56:17.893 UTC

null

805,923

null

1,955,773

null

1

22

algorithm

11,495

The algorithm is indeed O(n). When iterating the array, use a variable to store the max value found so far, a variable to store the max value of subarray that ends at a[i], and another variable to store minimum value that ends at a[i] to treat negative values. <pre><code>float find_maximum(float arr[], int n) { if (n <= 0) return NAN; float max_at = arr[0]; // Maximum value that ends at arr[i] float min_at = arr[0]; // Minimum value that ends at arr[i] float max_value = max_at; for (int i = 1; i < n; i++) { float prev_max_at = max_at, prev_min_at = min_at; max_at = max(arr[i], arr[i] * prev_min_at, arr[i] * prev_max_at); min_at = min(arr[i], arr[i] * prev_min_at, arr[i] * prev_max_at); max_value = max(max_value, max_at); } return max_value; } </code></pre>

8,838,777

ERROR 1044 (42000): Access denied for user ''@'localhost' to database 'db'

I want to begin writing queries in MySQL. <code>show grants</code> shows: <pre><code>+--------------------------------------+ | Grants for @localhost | +--------------------------------------+ | GRANT USAGE ON *.* TO ''@'localhost' | +--------------------------------------+ </code></pre> I do not have any user-id but when I want to make a user I don't have privilleges, also I don't know how to make privileges when even I don't have one user! <pre><code>mysql> CREATE USER 'parsa'@'localhost' IDENTIFIED BY 'parsa'; ERROR 1227 (42000): Access denied; you need (at least one of) the CREATE USER pr ivilege(s) for this operation </code></pre> I tried to sign in as root: <pre><code>mysql> mysql -u root -p; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mysql -u root -p' at line 1 mysql> mysql -u root -p root; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mysql -u root -p root' at line 1 </code></pre>

8,839,017

12

null

2012-01-12 16:44:00.207 UTC

68

2022-04-06 15:08:33.437 UTC

2012-10-20 21:43:14.24 UTC

null

128,421

null

974,380

null

1

192

mysql

855,056

No, you should run <code>mysql -u root -p</code> in bash, not at the MySQL command-line. If you are in mysql, you can exit by typing exit.

20,625,582

How to deal with SettingWithCopyWarning in Pandas

<h2>Background</h2> I just upgraded my Pandas from 0.11 to 0.13.0rc1. Now, the application is popping out many new warnings. One of them like this: <pre class="lang-none prettyprint-override"><code>E:\FinReporter\FM_EXT.py:449: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_index,col_indexer] = value instead quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE </code></pre> I want to know what exactly it means? Do I need to change something? How should I suspend the warning if I insist to use <code>quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE</code>? <h2>The function that gives errors</h2> <pre><code>def _decode_stock_quote(list_of_150_stk_str): """decode the webpage and return dataframe""" from cStringIO import StringIO str_of_all = "".join(list_of_150_stk_str) quote_df = pd.read_csv(StringIO(str_of_all), sep=',', names=list('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefg')) #dtype={'A': object, 'B': object, 'C': np.float64} quote_df.rename(columns={'A':'STK', 'B':'TOpen', 'C':'TPCLOSE', 'D':'TPrice', 'E':'THigh', 'F':'TLow', 'I':'TVol', 'J':'TAmt', 'e':'TDate', 'f':'TTime'}, inplace=True) quote_df = quote_df.ix[:,[0,3,2,1,4,5,8,9,30,31]] quote_df['TClose'] = quote_df['TPrice'] quote_df['RT'] = 100 * (quote_df['TPrice']/quote_df['TPCLOSE'] - 1) quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE quote_df['TAmt'] = quote_df['TAmt']/TAMT_SCALE quote_df['STK_ID'] = quote_df['STK'].str.slice(13,19) quote_df['STK_Name'] = quote_df['STK'].str.slice(21,30)#.decode('gb2312') quote_df['TDate'] = quote_df.TDate.map(lambda x: x[0:4]+x[5:7]+x[8:10]) return quote_df </code></pre> <h2>More error messages</h2> <pre class="lang-none prettyprint-override"><code>E:\FinReporter\FM_EXT.py:449: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_index,col_indexer] = value instead quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE E:\FinReporter\FM_EXT.py:450: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_index,col_indexer] = value instead quote_df['TAmt'] = quote_df['TAmt']/TAMT_SCALE E:\FinReporter\FM_EXT.py:453: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_index,col_indexer] = value instead quote_df['TDate'] = quote_df.TDate.map(lambda x: x[0:4]+x[5:7]+x[8:10]) </code></pre>

20,627,316

20

5

null

2013-12-17 03:48:02.57 UTC

436

2022-09-21 16:06:52.823 UTC

2022-09-21 15:27:21.043 UTC

null

63,550

null

1,072,888

null

1

1,220

python|pandas|dataframe|chained-assignment

1,676,151

The <code>SettingWithCopyWarning</code> was created to flag potentially confusing "chained" assignments, such as the following, which does not always work as expected, particularly when the first selection returns a copy. [see <a href="https://github.com/pydata/pandas/pull/5390" rel="noreferrer">GH5390</a> and <a href="https://github.com/pydata/pandas/issues/5597" rel="noreferrer">GH5597</a> for background discussion.] <pre><code>df[df['A'] > 2]['B'] = new_val # new_val not set in df </code></pre> The warning offers a suggestion to rewrite as follows: <pre><code>df.loc[df['A'] > 2, 'B'] = new_val </code></pre> However, this doesn't fit your usage, which is equivalent to: <pre><code>df = df[df['A'] > 2] df['B'] = new_val </code></pre> While it's clear that you don't care about writes making it back to the original frame (since you are overwriting the reference to it), unfortunately this pattern cannot be differentiated from the first chained assignment example. Hence the (false positive) warning. The potential for false positives is addressed in the <a href="https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy" rel="noreferrer">docs on indexing</a>, if you'd like to read further. You can safely disable this new warning with the following assignment. <pre><code>import pandas as pd pd.options.mode.chained_assignment = None # default='warn' </code></pre> <hr /> <h2>Other Resources</h2> <ul> <li><a href="https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html" rel="noreferrer">pandas User Guide: Indexing and selecting data</a></li> <li><a href="https://jakevdp.github.io/PythonDataScienceHandbook/03.02-data-indexing-and-selection.html" rel="noreferrer">Python Data Science Handbook: Data Indexing and Selection</a></li> <li><a href="https://realpython.com/pandas-settingwithcopywarning/" rel="noreferrer">Real Python: SettingWithCopyWarning in Pandas: Views vs Copies</a></li> <li><a href="https://www.dataquest.io/blog/settingwithcopywarning/" rel="noreferrer">Dataquest: SettingwithCopyWarning: How to Fix This Warning in Pandas</a></li> <li><a href="https://towardsdatascience.com/explaining-the-settingwithcopywarning-in-pandas-ebc19d799d25" rel="noreferrer">Towards Data Science: Explaining the SettingWithCopyWarning in pandas</a></li> </ul>

20,828,907

The new syntax "= default" in C++11

I don't understand why would I ever do this: <pre><code>struct S { int a; S(int aa) : a(aa) {} S() = default; }; </code></pre> Why not just say: <pre><code>S() {} // instead of S() = default; </code></pre> why bring in a new syntax for that?

20,828,970

6

null

2013-12-29 19:01:59.383 UTC

74

2022-09-17 21:45:30.223 UTC

2019-07-14 00:36:13.043 UTC

null

9,716,597

null

3,111,311

null

1

188

c++|c++11

98,721

A defaulted default constructor is specifically defined as being the same as a user-defined default constructor with no initialization list and an empty compound statement. <blockquote> §12.1/6 [class.ctor] A default constructor that is defaulted and not defined as deleted is implicitly defined when it is odr-used to create an object of its class type or when it is explicitly defaulted after its first declaration. The implicitly-defined default constructor performs the set of initializations of the class that would be performed by a user-written default constructor for that class with no ctor-initializer (12.6.2) and an empty compound-statement. [...] </blockquote> However, while both constructors will behave the same, providing an empty implementation does affect some properties of the class. Giving a user-defined constructor, even though it does nothing, makes the type not an aggregate and also not trivial. If you want your class to be an aggregate or a trivial type (or by transitivity, a POD type), then you need to use <code>= default</code>. <blockquote> §8.5.1/1 [dcl.init.aggr] An aggregate is an array or a class with no user-provided constructors, [and...] </blockquote> <blockquote> §12.1/5 [class.ctor] A default constructor is trivial if it is not user-provided and [...] §9/6 [class] A trivial class is a class that has a trivial default constructor and [...] </blockquote> To demonstrate: <pre><code>#include <type_traits> struct X { X() = default; }; struct Y { Y() { }; }; int main() { static_assert(std::is_trivial<X>::value, "X should be trivial"); static_assert(std::is_pod<X>::value, "X should be POD"); static_assert(!std::is_trivial<Y>::value, "Y should not be trivial"); static_assert(!std::is_pod<Y>::value, "Y should not be POD"); } </code></pre> Additionally, explicitly defaulting a constructor will make it <code>constexpr</code> if the implicit constructor would have been and will also give it the same exception specification that the implicit constructor would have had. In the case you've given, the implicit constructor would not have been <code>constexpr</code> (because it would leave a data member uninitialized) and it would also have an empty exception specification, so there is no difference. But yes, in the general case you could manually specify <code>constexpr</code> and the exception specification to match the implicit constructor. Using <code>= default</code> does bring some uniformity, because it can also be used with copy/move constructors and destructors. An empty copy constructor, for example, will not do the same as a defaulted copy constructor (which will perform member-wise copy of its members). Using the <code>= default</code> (or <code>= delete</code>) syntax uniformly for each of these special member functions makes your code easier to read by explicitly stating your intent.

11,193,983

Android save List<String>

Is there anyway I can save a List variable to the Androids phone internal or external memory? I know I can save primitive data, yet not sure about this one. Thanks in advance.

11,194,200

3

null

2012-06-25 17:10:56.34 UTC

8

2022-05-22 17:12:14.727 UTC

null

1,297,445

null

1

15

android|list|save

78,067

Yes exactly you can only save primitives so you could something like this: <pre><code>List<String> list = new ArrayList<String>(); list.add("one"); list.add("two"); list.add("three"); StringBuilder csvList = new StringBuilder(); for(String s : list){ csvList.append(s); csvList.append(","); } sharedPreferencesEditor.put("myList", csvList.toString()); </code></pre> Then to create your <code>list</code> again you would: <pre><code>String csvList = sharedPreferences.getString("myList"); String[] items = csvList.split(","); List<String> list = new ArrayList<String>(); for(int i=0; i < items.length; i++){ list.add(items[i]); } </code></pre> You could encapsulate this "serializing" into your own class wrapping a list to keep it nice and tidy. Also you could look at converting your <code>list</code> to <code>JSON</code>.

10,943,033

Why are strings in C++ usually terminated with '\0'?

In many code samples, people usually use <code>'\0'</code> after creating a new char array like this: <pre><code>string s = "JustAString"; char* array = new char[s.size() + 1]; strncpy(array, s.c_str(), s.size()); array[s.size()] = '\0'; </code></pre> Why should we use <code>'\0'</code> here?

10,943,040

5

7

null

2012-06-08 04:22:05.94 UTC

11

2022-04-12 13:59:25.367 UTC

null

995,714

null

972,671

null

1

20

c++|c|string|null-terminated

62,309

The title of your question references C strings. C++ <code>std::string</code> objects are handled differently than standard C strings. <code>\0</code> is important when using C strings, and when I use the term string in this answer, I'm referring to standard C strings. <code>\0</code> acts as a string terminator in C. It is known as the null character, or NUL, and standard C strings are null-terminated. This terminator signals code that processes strings - standard libraries but also your own code - where the end of a string is. A good example is <code>strlen</code> which returns the length of a string: <code>strlen</code> works using the assumption that it operates on strings that are terminated using <code>\0</code>. When you declare a constant string with: <pre><code>const char *str = "JustAString"; </code></pre> then the <code>\0</code> is appended automatically for you. In other cases, where you'll be managing a non-constant string as with your array example, you'll sometimes need to deal with it yourself. The <a href="http://en.cppreference.com/w/c/string/byte/strncpy" rel="nofollow noreferrer">docs for strncpy</a>, which is used in your example, are a good illustration: <code>strncpy</code> copies over the null terminator character except in the case where the specified length is reached before the entire string is copied. Hence you'll often see <code>strncpy</code> combined with the possibly redundant assignment of a null terminator. <code>strlcpy</code> and <code>strcpy_s</code> were designed to address the potential problems that arise from neglecting to handle this case. In your particular example, <code>array[s.size()] = '\0';</code> is one such redundancy: since <code>array</code> is of size <code>s.size() + 1</code>, and <code>strncpy</code> is copying <code>s.size()</code> characters, the function will append the <code>\0</code>. The documentation for standard C string utilities will indicate when you'll need to be careful to include such a null terminator. But read the documentation carefully: as with <code>strncpy</code> the details are easily overlooked, leading to potential buffer overflows.

11,006,634

Any VI like editor under windows?

I am wondering whether there is a vi like editor under windows command line?

11,006,648

2

4

null

2012-06-13 00:18:52.24 UTC

3

2015-07-03 02:05:59.467 UTC

2014-01-16 12:48:20.75 UTC

user146043

null

1,136,700

null

1

25

windows|vim|windows-7|vi

75,471

Just download vim for windows from <a href="http://www.vim.org" rel="noreferrer">http://www.vim.org</a> -- on the installation it will ask if you want to create shortcuts for calling it from the command line. Then you can just <code>vim <filename></code>.

11,223,868

How to create ByteArrayInputStream from a file in Java?

I have a file that can be any thing like ZIP, RAR, txt, CSV, doc etc. I would like to create a ByteArrayInputStream from it. I'm using it to upload a file to FTP through FTPClient from Apache Commons Net. Does anybody know how to do it? For example: <pre><code>String data = "hdfhdfhdfhd"; ByteArrayInputStream in = new ByteArrayInputStream(data.getBytes()); </code></pre> My code: <pre><code>public static ByteArrayInputStream retrieveByteArrayInputStream(File file) { ByteArrayInputStream in; return in; } </code></pre>

11,223,955

5

7

null

2012-06-27 10:12:56.817 UTC

8

2019-09-01 12:01:50.147 UTC

2017-09-05 09:18:00.96 UTC

null

6,256,127

null

1,092,450

null

1

31

java|arrays|bytebuffer|bytearrayinputstream

109,543

Use the <a href="http://commons.apache.org/io/api-release/org/apache/commons/io/FileUtils.html#readFileToByteArray%28java.io.File%29" rel="noreferrer"><code>FileUtils#readFileToByteArray(File)</code></a> from <a href="http://commons.apache.org/io" rel="noreferrer">Apache Commons IO</a>, and then create the <code>ByteArrayInputStream</code> using the <a href="http://docs.oracle.com/javase/1.4.2/docs/api/java/io/ByteArrayInputStream.html#ByteArrayInputStream%28byte[]%29" rel="noreferrer"><code>ByteArrayInputStream(byte[])</code></a> constructor. <pre><code>public static ByteArrayInputStream retrieveByteArrayInputStream(File file) { return new ByteArrayInputStream(FileUtils.readFileToByteArray(file)); } </code></pre>

11,074,671

adb pull multiple files

What is the best way to pull multiple files using <pre><code>adb pull </code></pre> I have on my <code>/sdcard/</code> 25 files with following name: <pre><code>gps1.trace gps2.trace ... gps25.trace </code></pre> Wildcard does not work: <pre><code>adb pull /sdcard/gps*.trace . </code></pre>

11,250,068

13

3

null

2012-06-17 20:47:32.327 UTC

33

2021-09-07 14:44:00.023 UTC

2018-12-31 07:03:37.61 UTC

null

223,386

null

223,386

null

1

95

android|adb

102,954

You can use <code>xargs</code> and the result of the <code>adb shell ls</code> command which accepts wildcards. This allows you to copy multiple files. Annoyingly the output of the <code>adb shell ls</code> command includes line-feed control characters that you can remove using <code>tr -d '\r'</code>. Examples: <pre><code># Using a relative path adb shell 'ls sdcard/gps*.trace' | tr -d '\r' | xargs -n1 adb pull # Using an absolute path adb shell 'ls /sdcard/*.txt' | tr -d '\r' | sed -e 's/^\///' | xargs -n1 adb pull </code></pre>

13,142,419

General way of solving Error: Stack around the variable 'x' was corrupted

I have a program which prompts me the error in VS2010, in debug : <pre><code>Error: Stack around the variable 'x' was corrupted </code></pre> This gives me the function where a stack overflow likely occurs, but I can't visually see where the problem is. Is there a general way to debug this error with VS2010? Would it be possible to indentify which write operation is overwritting the incorrect stack memory? thanks

13,143,133

9

6

null

2012-10-30 15:32:18.033 UTC

7

2021-02-01 09:36:03.293 UTC

null

875,295

null

1

26

c++|visual-studio-2010|debugging

70,533

<blockquote> Is there a general way to debug this error with VS2010? </blockquote> No, there isn't. What you have done is to somehow invoke undefined behavior. The reason these behaviors are undefined is that the general case is very hard to detect/diagnose. Sometimes it is provably impossible to do so. There are however, a somewhat smallish number of things that typically cause your problem: <ul> <li>Improper handling of memory: <ul> <li>Deleting something twice,</li> <li>Using the wrong type of deletion (<code>free</code> for something allocated with <code>new</code>, etc.),</li> <li>Accessing something after it's memory has been deleted.</li> </ul></li> <li>Returning a pointer or reference to a local.</li> <li>Reading or writing past the end of an array.</li> </ul>

13,170,493

Build once and deploy to multiple environments with msdeploy & Visual Studio 2012

Working on centralizing configurations, app settings and connection strings, for multiple solutions, while also switching over to use msdeploy from command line to deploy web apps. Ideally I would want to build the packages once, and get up-to-date configurations as the packages are deployed to each environment. I need some advice on the best approach to take. <ol> <li>Use Parameters.xml and SetParameters.xml file to dynamically swap out settings and connection strings. See <a href="http://vishaljoshi.blogspot.com/2010/07/web-deploy-parameterization-in-action.html" rel="noreferrer">http://vishaljoshi.blogspot.com/2010/07/web-deploy-parameterization-in-action.html</a></li> <li>Use machine.config or server level web.config files to store common app settings and connection strings.</li> <li>Use packageweb NuGet package from <a href="https://github.com/sayedihashimi/package-web" rel="noreferrer">https://github.com/sayedihashimi/package-web</a> which enables using web.config transforms with msdeploy.</li> <li>Use file or configSource attributes along with SetParameters to point to different config files, but must be relative from web root.</li> <li>Use publish profiles. See <a href="https://stackoverflow.com/questions/11683243/deploying-an-existing-package-using-publish-profiles">Deploying an existing package using publish profiles</a></li> </ol> Thanks

13,258,269

4

0

null

2012-11-01 03:21:01.84 UTC

18

2014-10-15 23:16:01.447 UTC

2017-05-23 12:31:59.927 UTC

null

-1

null

753,279

null

1

39

msbuild|msdeploy

22,243

We use option #1 and it works out well enough. We deploy to about 30-40 sites and applications using this approach. I think option #2 will cause headaches for either you or the developers. You'll either have to make sure the sections with settings are removed from the config on deployment, or lock them on the server so that the local config can't add them. For option #3 you will have to do multiple builds to get the transformed config files. It also isn't very feasible if you have a large number of sites to deploy. Option #4 could work, but you might run into limitations here. It's either the whole section is in a separate file or its all in the main file so there's no in-between. Option #5 looks interesting, but I haven't used it so I can't say much about it.

16,582,107

Android studio doesn't start

I just download Android Studio for Windows 7, the wizard went ok up to the end but now when I click on the shortcut or on the .exe to start the program nothing happens, no error, no new window, it's seems like it is doing nothing. Do you have any suggestion?

16,582,314

16

4

null

2013-05-16 08:07:15.333 UTC

2

2020-12-16 01:45:04.593 UTC

null

1,012,909

null

1

29

windows-7|android-studio

35,025

It's a bug of Android Studio 0.1v You should add <code>JAVA_HOME</code> to the system environment variables. <a href="http://tools.android.com/knownissues#as0.1" rel="noreferrer">http://tools.android.com/knownissues#as0.1</a> <ul> <li>Open Start menu > computer > System Properties > Advanced System Properties </li> <li>In the Advanced tab > Environment Variables, add new system variable <code>JAVA_HOME</code> that points to your JDK folder, for example <code>C:\Program Files\Java\jdk1.7.0_21</code></li> </ul>

26,906,630

Django Rest Framework - Authentication credentials were not provided

I'm developing an API using Django Rest Framework. I'm trying to list or create an "Order" object, but when i'm trying to access the console gives me this error: <pre><code>{"detail": "Authentication credentials were not provided."} </code></pre> Views: <pre><code>from django.shortcuts import render from rest_framework import viewsets from django.contrib.auth.models import User from rest_framework.renderers import JSONRenderer, YAMLRenderer from rest_framework.response import Response from rest_framework.views import APIView from order.models import * from API.serializers import * from rest_framework.permissions import IsAuthenticated class OrderViewSet(viewsets.ModelViewSet): model = Order serializer_class = OrderSerializer permission_classes = (IsAuthenticated,) </code></pre> Serializer: <pre><code>class OrderSerializer(serializers.HyperlinkedModelSerializer): class Meta: model = Order fields = ('field1', 'field2') </code></pre> And my URLs: <pre><code># -*- coding: utf-8 -*- from django.conf.urls import patterns, include, url from django.conf import settings from django.contrib import admin from django.utils.functional import curry from django.views.defaults import * from rest_framework import routers from API.views import * admin.autodiscover() handler500 = "web.views.server_error" handler404 = "web.views.page_not_found_error" router = routers.DefaultRouter() router.register(r'orders', OrdersViewSet) urlpatterns = patterns('', url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework')), url(r'^api-token-auth/', 'rest_framework.authtoken.views.obtain_auth_token'), url(r'^api/', include(router.urls)), ) </code></pre> And then I'm using this command in the console: <pre><code>curl -X GET http://127.0.0.1:8000/api/orders/ -H 'Authorization: Token 12383dcb52d627eabd39e7e88501e96a2sadc55' </code></pre> And the error say: <pre><code>{"detail": "Authentication credentials were not provided."} </code></pre>

26,907,225

15

4

null

2014-11-13 10:27:45.653 UTC

47

2022-06-09 05:40:03.197 UTC

2014-11-13 10:48:19.387 UTC

null

1,967,886

null

1,967,886

null

1

141

python|django|django-rest-framework

169,463

Solved by adding "DEFAULT_AUTHENTICATION_CLASSES" to my settings.py <pre><code>REST_FRAMEWORK = { 'DEFAULT_AUTHENTICATION_CLASSES': ( 'rest_framework.authentication.TokenAuthentication', ), 'DEFAULT_PERMISSION_CLASSES': ( 'rest_framework.permissions.IsAdminUser' ), } </code></pre>

41,432,852

Why would I want to use an ExpressionVisitor?

I know from the MSDN's article about <a href="https://msdn.microsoft.com/en-us/library/mt654266.aspx" rel="noreferrer">How to: Modify Expression Trees</a> what an <code>ExpressionVisitor</code> is supposed to do. It should modify expressions. Their example is however pretty unrealistic so I was wondering why would I need it? Could you name some real-world cases where it would make sense to modify an expression tree? Or, why does it have to be modified at all? From what to what? It has also many overloads for visiting all kinds of expressions. How do I know when I should use any of them and what should they return? I saw people using <code>VisitParameter</code> and returning <code>base.VisitParameter(node)</code> the other on the other hand were returning <code>Expression.Parameter(..)</code>.

41,653,475

4

8

null

2017-01-02 20:21:52.467 UTC

8

2018-04-13 23:30:11.467 UTC

2017-01-02 20:35:51.31 UTC

null

235,671

null

235,671

null

1

33

c#|expression-trees|expressionvisitor

13,135

<blockquote> Could you name some real-world cases where it would make sense to modify an expression tree? </blockquote> Strictly speaking, we never modify an expression tree, as they are immutable (as seen from the outside, at least, there's no promise that it doesn't internally memoise values or otherwise have mutable private state). It's precisely because they are immutable and hence we can't just change a node that the visitor pattern makes a lot of sense if we want to create a new expression tree that is based on the one we have but different in some particular way (the closest thing we have to modifying an immutable object). We can find a few within Linq itself. In many ways the simplest Linq provider is the linq-to-objects provider that works on enumerable objects in memory. When it receives enumerables directly as <code>IEnumerable<T></code> objects it's pretty straight-forward in that most programmers could write an unoptimised version of most of the methods pretty quickly. E.g. <code>Where</code> is just: <pre><code>foreach (T item in source) if (pred(item)) yield return item; </code></pre> And so on. But what about <code>EnumerableQueryable</code> implementing the <code>IQueryable<T></code> versions? Since the <code>EnumerableQueryable</code> wraps an <code>IEnumerable<T></code> we could do the desired operation on the one or more enumerable objects involved, but we have an expression describing that operation in terms of <code>IQueryable<T></code> and other expressions for selectors, predicates, etc, where what we need is a description of that operation in terms of <code>IEnumerable<T></code> and delegates for selectors, predicates, etc. <a href="https://github.com/dotnet/corefx/blob/master/src/System.Linq.Queryable/src/System/Linq/EnumerableRewriter.cs" rel="noreferrer"><code>System.Linq.EnumerableRewriter</code></a> is an implementation of <code>ExpressionVisitor</code> does exactly such a re-write, and the result can then simply be compiled and executed. Within <code>System.Linq.Expressions</code> itself there are a few implementations of <code>ExpressionVisitor</code> for different purposes. One example is that the interpreter form of compilation can't handle hoisted variables in quoted expressions directly, so it uses a visitor to rewrite it into working on indices into a a dictionary. As well as producing another expression, an <code>ExpressionVisitor</code> can produce another result. Again <code>System.Linq.Expressions</code> has internal examples itself, with debug strings and <code>ToString()</code> for many expression types working by visiting the expression in question. This can (though it doesn't have to be) be the approach used by a database-querying linq provider to turn an expression into a SQL query. <blockquote> How do I know when I should use any of them and what should they return? </blockquote> The default implementation of these methods will: <ol> <li>If the expression can have no child expressions (e.g. the result of <code>Expression.Constant()</code>) then it will return the node back again.</li> <li>Otherwise visit all the child expressions, and then call <code>Update</code> on the expression in question, passing the results back. <code>Update</code> in turn will either return a new node of the same type with the new children, or return the same node back again if the children weren't changed.</li> </ol> As such, if you don't know you need to explicitly operate on a node for whatever your purposes are, then you probably don't need to change it. It also means that <code>Update</code> is a convenient way to get a new version of a node for a partial change. But just what "whatever your purposes are" means of course depends on the use case. The most common cases are probably go to one extreme or the other, with either just one or two expression types needing an override, or all or nearly all needing it. (One caveat is if you are examining the children of those nodes that have children in a <code>ReadOnlyCollection</code> such as <code>BlockExpression</code> for both its steps and variables or <code>TryExpression</code> for its catch-blocks, and you will only sometimes change those children then if you haven't changed you are best to check for this yourself as a flaw [recently fixed, but not in any released version yet] means that if you pass the same children to <code>Update</code> in a different collection to the original <code>ReadOnlyCollection</code> then a new expression is created needlessly which has effects further up the tree. This is normally harmless, but it wastes time and memory).

9,826,699

ASP.NET - Passing a C# variable to HTML

I am trying to pass variables declared in C# to html. The variables have all been declared as public in the code-behind. This is the HTML code I am using: <pre><code><asp:TextBox ID="TextBoxChildID" Text='<%= Child_ID %>' runat="server" Enabled="false"></asp:TextBox> </code></pre> The problem is that when the page loads, the text '<%= Child_ID %>' appears in the textbox instead of the value in the variable. What is wrong please?

9,826,732

4

0

null

2012-03-22 16:41:29.88 UTC

null

2019-10-31 21:17:46.36 UTC

null

1,839,439

null

1,124,249

null

1

9

c#|asp.net

51,812

All of this is assuming that this is just a textbox somewhere on your page, rather than in a DataBound control. If the textbox is part of an itemTemplate in a repeater, and Child_ID is something that differes by data row, then all of this is incorrect. Do this instead: <pre><code><asp:TextBox ID="TextBoxChildID" runat="server" Enabled="false"><%= Child_ID %></asp:TextBox> </code></pre> In short, you're making the same mistake I was making when I asked this question: <a href="https://stackoverflow.com/questions/1531586/why-works-in-one-situation-but-not-in-another">Why <%= %> works in one situation but not in another</a> <hr> Alternatively, in code-behind, you can have this in your ASPX: <pre><code><asp:TextBox ID="TextBoxChildID" runat="server" Enabled="false"></asp:TextBox> </code></pre> and this in your Code-Behind: <pre><code>TextBoxChildID.Text = Child_ID; </code></pre>

10,199,863

How to execute the dex file in android with command?

Can any body please share the method to execute the dex file in android with command? This is just to understand.

10,200,822

1

null

2012-04-17 22:03:25.007 UTC

18

2018-08-06 07:09:20.97 UTC

null

1,015,097

null

1

19

android|dex

14,365

Let's say you have a the following code in file HelloWorld.java: <pre><code>public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } </code></pre> To run it on an android device: <pre><code>javac HelloWorld.java dx --dex --output=classes.dex HelloWorld.class zip HelloWorld.zip classes.dex adb push HelloWorld.zip /sdcard/ </code></pre> For GB or earlier, you should be able to simply do: <pre><code>adb shell dalvikvm -cp /sdcard/HelloWorld.zip HelloWorld </code></pre> For ICS+: <pre><code>adb shell mkdir /sdcard/dalvik-cache adb shell ANDROID_DATA=/sdcard dalvikvm -cp /sdcard/HelloWorld.zip HelloWorld </code></pre>

9,795,051

When to use R, when to use SQL?

I have a moderate sized database with many joins and lookup tables. I am more familiar with R than with SQL, and I am using MySQL. <h2>My Question:</h2> At what point is it beneficial to stop increasing the complexity of an SQL statement in favor of the data subsetting functionality in R (e.g., <code>merge</code>, <code>*apply</code>, <code>maply</code>, <code>dlply</code>, etc.)in R. On one hand, SQL's join is easier than selecting all contents of each table and using the R <code>merge</code> function to join them. Also, doing the conditional selects in SQL would reduce the amount of data that has to be imported to R; but the speed difference is not significant. On the other hand, a big join with a complex where clause becomes less easy to understand than the R syntax. Below I have some untested code for illustrative purposes: I am asking this question at before having working code, and the answer to my question doesn't require working code (although this is always appreciated) - the "most elegant approach", "fewest lines", or "amazing implementation of X" are always appreciated, but what I am particularly interested in is the "most sensible / practical / canonical / based on first principles" rationale. I am interested in the general answer of which steps should use a SQL <code>where</code> clause and which steps would be easier to accomplish using R. <h2>Illustration:</h2> <h3>Database description</h3> there are three tables: <code>a</code>, <code>ab</code>, and <code>b</code>. Tables <code>a</code> and <code>b</code> each have a primary key <code>id</code>. They have a many-many relationship that is represented by a lookup table, <code>ab</code>, which contains fields <code>ab.a_id</code> and <code>ab.b_id</code> that join to <code>a.id</code> and <code>b.id</code>, respectively. Both tables have a <code>time</code> field, and a has a <code>group</code> field. <h3>Goal:</h3> Here is a minimal example of the join and subsetting that I want to do; (MySQL naming of elements, e.g. <code>a.id</code> is equivalent to <code>a$id</code> in R) <ol> <li>Join tables <code>a</code> and <code>b</code> using <code>ab</code>, appending multiple values of <code>b.time</code> associated with each <code>a.id</code> as a new column; <pre><code>select a_time, b.time, a.id, b.id from a join ab on a.id = ab.a_id join b on b.id = ab.b_id and then append b.time for distinct values of b.id; </code></pre></li> <li>I don't need repeated values of b.time, I only need a value of <code>b.max</code>: for repeated values of <code>b.time</code> joined to each <code>a.id</code>, <code>b.max</code> is the value of <code>b.time</code> closest to but not greater than <code>a.time</code> <pre><code>b.max <- max(b.time[b.time < a.time)) </code></pre></li> <li>append the value <code>dt <- a.time - b.max</code> to the table, for example, in R, </li> <li>for each distinct value in <code>a.group</code>, select which(min(x.dt))) <pre><code>x.dt <- a.time - b.max </code></pre></li> </ol>

9,796,652

2

1

null

2012-03-20 21:13:00.63 UTC

9

2015-12-04 13:37:28.227 UTC

null

4,370,109

null

199,217

null

1

29

sql|r|database|data.table

19,295

I usually do the data manipulations in SQL until the data I want is in a single table, and then, I do the rest in R. Only when there is a performance issue do I start to move some of the computations to the database. This is already what you are doing. Computations involving timestamps often become unreadable in SQL (the "<a href="http://en.wikipedia.org/wiki/Select_%28SQL%29#Window_function">analytic functions</a>", similar to <code>ddply</code>, are supposed to simplify this, but I think they are not available in MySQL). However, your example can probably be written entirely in SQL as follows (not tested). <pre><code>-- Join the tables and compute the maximum CREATE VIEW t1 AS SELECT a.id AS a_id, a.group AS a_group, b.id AS b_id, a.time AS a_time, a.time - MAX(b.time) AS dt FROM a, b, ab WHERE a.id = ab.a_id AND b.id = ab.b_id AND b.time < a.time GROUP BY a.id, a.group, b.id; -- Extract the desired rows CREATE VIEW t2 AS SELECT t1.* FROM t1, (SELECT group, MIN(dt) AS min_dt FROM t1) X WHERE t1.a_id = X.a_id AND t1.b_id = X.b_id AND t1.a_group = X.a.group; </code></pre>

7,918,270

How to purge all tasks of a specific queue with celery in python?

How to purge all scheduled and running tasks of a specific que with celery in python? The questions seems pretty straigtforward, but to add I am not looking for the command line code I have the following line, which defines the que and would like to purge that que to manage tasks: <pre><code>CELERY_ROUTES = {"socialreport.tasks.twitter_save": {"queue": "twitter_save"}} </code></pre> At 1 point in time I wanna purge all tasks in the que twitter_save with python code, maybe with a broadcast function? I couldn't find the documentation about this. Is this possible?

20,410,181

3

0

null

2011-10-27 15:23:28.837 UTC

9

2016-07-14 13:04:26.17 UTC

2014-06-05 22:05:52.777 UTC

null

402,884

null

376,445

null

1

18

python|django|celery

15,265

just to update @Sam Stoelinga answer for celery 3.1, now it can be done like this on a terminal: <pre><code>celery amqp queue.purge <QUEUE_NAME> </code></pre> For Django be sure to start it from the manage.py file: <pre><code>./manage.py celery amqp queue.purge <QUEUE_NAME> </code></pre> If not, be sure celery is able to point correctly to the broker by setting the <code>--broker=</code> flag.

11,689,155

Basic MVC (PHP) Structure

I have the following data flow for a simple login form. User access controller PHP file. Controller includes model.php and view.php User submits form, controller sends POST data to model methods, and gets a result back. User is logged in, and forwarded to a different view (login success message) by the controller. Currently my views are static HTML (no PHP), so here is my question. What is the correct way to then pass the user a welcome message, e.g "Hello, Craig!"? Is the view allowed PHP snippets, e.g <pre><code><?php echo $username; ?> </code></pre> since the model is loaded before it in the controller file? Thanks! Edit: Is it better practice then to allow the view to access specific class methods e.g <pre><code><?php $user->getUsername(); ?> </code></pre> as opposed to just variables? <hr> Based on other answers, I have found a very useful article, which you may also be interested in. <a href="http://www.nathandavison.com/posts/view/7/custom-php-mvc-tutorial-part-5-views" rel="noreferrer">http://www.nathandavison.com/posts/view/7/custom-php-mvc-tutorial-part-5-views</a>

11,689,228

2

3

null

2012-07-27 13:49:51.16 UTC

12

2019-07-22 08:32:22 UTC

2013-02-20 18:55:57.833 UTC

null

2,598

null

1,504,434

null

1

9

php|model-view-controller

24,398

You can really put anything in a view that you'd like, but to better adhere to the MVC way of doing things you should restrict PHP in the view to simple <code>echo</code>s or <code>print</code>s (possibly really small loops as well, although even those can be pre-calculated in the controller/model). Since that is the only way to get dynamic content, it would be a little silly to say that they are not allowed. The idea of the view is to let it have a more HTML look-and-feel, so that front-end developers or people who don't know PHP can easily be able to work with the file without getting confused. Update To learn more about MVC in general, you can see any of these (there's a ton of tutorials out there): <a href="http://blog.iandavis.com/2008/12/09/what-are-the-benefits-of-mvc/" rel="noreferrer">http://blog.iandavis.com/2008/12/09/what-are-the-benefits-of-mvc/</a> <a href="http://php-html.net/tutorials/model-view-controller-in-php/" rel="noreferrer">http://php-html.net/tutorials/model-view-controller-in-php/</a> <a href="http://www.tonymarston.net/php-mysql/model-view-controller.html" rel="noreferrer">http://www.tonymarston.net/php-mysql/model-view-controller.html</a> To see concrete examples of PHP using MVC, I suggest downloading some of the more prevelant frameworks (such as <a href="http://codeigniter.com/" rel="noreferrer">CodeIgniter</a>, <a href="http://www.symfony-project.org/" rel="noreferrer">Symfony</a> or <a href="http://www.drupal.org/" rel="noreferrer">Drupal</a>) and just looking through the code. Try to figure out how it works and then recreate the functionality for a simple article-based system.

11,910,147

Trouble with importing annotations

I'm working on a CodeIgniter project in which I'm using Doctrine2 and the Symfony2 Validator component. All my Doctrine2 entities <code>use Doctrine\ORM\Mapping</code> and the entity manager recognizes them. My entity annotation looks like this: <pre><code>/** * @Entity(repositoryClass = "UserRepository") * @Table(name = "user") * @HasLifecycleCallbacks() */ </code></pre> At this point, I'm able to persist entities without any trouble. The first problem arises when I try to use the Symfony2 Validator component. When I try to validate a <code>User</code> object, I get this error: <blockquote> [Semantical Error] The annotation "@Entity" in class Entity\User was never imported. Did you maybe forget to add a "use" statement for this annotation? </blockquote> The only "fix" to this issue is through <code>use Doctrine\Mapping\Entity</code>, but I have to do that for every annotation being used by my entity (Table, Column, ManyToOne, etc.). I'm trying to figure out why I need to explicitely <code>use</code> each annotation class instead of them being automatically recognized (shouldn't <code>use Doctrine\ORM\Mapping</code> grant me access to all the classes within that namespace?). So, I then tried <code>use Doctrine\ORM\Mapping as ORM</code> and prefacing all my annotations with <code>ORM\</code>. Ex: <code>@ORM\Entity()</code>. The Symfony2 validator stops complaining, but now Doctrine2 complains that <code>Class Entity\User is not a valid entity or mapped super class.</code> I have no idea why this method works for the Validator, but not Doctrine2. If I run the console command <code>doctrine:orm:info</code>, my <code>User</code> entity is not recognized. Because this is a CodeIgniter app, I'm autoloading the Symfony2 and Doctrine2 libraries. My autoload code is as follows: <pre><code># Symfony2 ClassLoader component require_once __DIR__ . '/application/libraries/symfony/src/Symfony/Component/ClassLoader/UniversalClassLoader.php'; $loader = new \Symfony\Component\ClassLoader\UniversalClassLoader(); $loader->register(); $loader->registerNamespace('Symfony', __DIR__ . '/application/libraries/symfony/src'); $loader->registerNamespace('Doctrine', __DIR__ . '/application/libraries/doctrine/lib'); # Doctrine2 require_once __DIR__ . '/application/libraries/doctrine/lib/Doctrine/Common/Annotations/AnnotationRegistry.php'; use Doctrine\Common\Annotations\AnnotationRegistry; AnnotationRegistry::registerLoader(function($class) use ($loader) { $loader->loadClass($class); $classExists = class_exists($class, false); return $classExists; }); AnnotationRegistry::registerFile(__DIR__ . '/application/libraries/doctrine/lib/Doctrine/ORM/Mapping/Driver/DoctrineAnnotations.php'); </code></pre> I don't care if I have to preface everything with <code>ORM\</code> or not, I just want to find a solution that the Symfony2 Validator and Doctrine2 will both work with. Any ideas?

13,389,576

8

0

null

2012-08-10 22:40:29.58 UTC

1

2022-03-04 16:44:49.203 UTC

null

155,175

null

1

12

php|doctrine-orm

39,513

I had a similar issue when using Silex, Doctrine2 and the Symfony-Validator. The solution was to avoid using the SimpleAnnotationsReader and instead using the normal AnnotationReader (have a look at <a href="http://www.doctrine-project.org/api/orm/2.3/class-Doctrine.ORM.Configuration.html#_newDefaultAnnotationDriver" rel="noreferrer">Doctrine\ORM\Configuration::newDefaultAnnotationDriver</a>). You can then preface every entity with <code>ORM\</code> (and of course inserting <code>use Doctrine\ORM\Mapping as ORM;</code> in every entity).

11,759,040

Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException:

I am creating web application using Spring, Hibernate, Struts, and Maven. I get the below error when I run <code>mvn clean install</code> command: <pre><code>org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.project.action.PasswordHintActionTest': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.project.action.PasswordHintAction com.project.action.PasswordHintActionTest.action; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.project.action.PasswordHintAction] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} </code></pre> The following is the class that has the Autowired dependency: <pre><code>import com.opensymphony.xwork2.Action; import org.project.model.User; import org.proejct.service.UserManager; import org.junit.Test; import org.springframework.beans.factory.annotation.Autowired; import org.subethamail.wiser.Wiser; import static org.junit.Assert.*; public class PasswordHintActionTest extends BaseActionTestCase { @Autowired private PasswordHintAction action; @Autowired private UserManager userManager; @Test public void testExecute() throws Exception { // start SMTP Server Wiser wiser = new Wiser(); wiser.setPort(getSmtpPort()); wiser.start(); action.setUsername("user"); assertEquals("success", action.execute()); assertFalse(action.hasActionErrors()); // verify an account information e-mail was sent wiser.stop(); assertTrue(wiser.getMessages().size() == 1); // verify that success messages are in the request assertNotNull(action.getSession().getAttribute("messages")); } } </code></pre> My <code>applicationcontext.xml</code> <pre><code><?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd" default-lazy-init="true">  <context:annotation-config/>  <context:component-scan base-package="com.project"/>    <bean id="compass" class="org.compass.spring.LocalCompassBean"> <property name="mappingScan" value="org.project"/> <property name="postProcessor" ref="compassPostProcessor"/> <property name="transactionManager" ref="transactionManager" /> <property name="settings"> <map> <entry key="compass.engine.connection" value="target/test-index" /> </map> </property> </bean> </code></pre> I have added to my context configuration to scan Autowired dependencies. But I am not sure why it is still giving this exception. I tried adding it in following way also but I still get the same exception <pre><code><context:component-scan base-package="com.project.*"/> </code></pre> UPDATE: following is the password hint action <pre><code>import org.project.model.User; import com.project.webapp.util.RequestUtil; import org.springframework.mail.MailException; import org.springframework.security.core.userdetails.UsernameNotFoundException; import java.util.ArrayList; import java.util.List; public class PasswordHintAction extends BaseAction { private static final long serialVersionUID = -4037514607101222025L; private String username; /** * @param username The username to set. */ public void setUsername(String username) { this.username = username; } /** * Execute sending the password hint via e-mail. * * @return success if username works, input if not */ public String execute() { List<Object> args = new ArrayList<Object>(); // ensure that the username has been sent if (username == null) { log.warn("Username not specified, notifying user that it's a required field."); args.add(getText("user.username")); addActionError(getText("errors.requiredField", args)); return INPUT; } if (log.isDebugEnabled()) { log.debug("Processing Password Hint..."); } // look up the user's information try { User user = userManager.getUserByUsername(username); String hint = user.getPasswordHint(); if (hint == null || hint.trim().equals("")) { log.warn("User '" + username + "' found, but no password hint exists."); addActionError(getText("login.passwordHint.missing")); return INPUT; } StringBuffer msg = new StringBuffer(); msg.append("Your password hint is: ").append(hint); msg.append("\n\nLogin at: ").append(RequestUtil.getAppURL(getRequest())); mailMessage.setTo(user.getEmail()); String subject = '[' + getText("webapp.name") + "] " + getText("user.passwordHint"); mailMessage.setSubject(subject); mailMessage.setText(msg.toString()); mailEngine.send(mailMessage); args.add(username); args.add(user.getEmail()); saveMessage(getText("login.passwordHint.sent", args)); } catch (UsernameNotFoundException e) { log.warn(e.getMessage()); args.add(username); addActionError(getText("login.passwordHint.error", args)); getSession().setAttribute("errors", getActionErrors()); return INPUT; } catch (MailException me) { addActionError(me.getCause().getLocalizedMessage()); getSession().setAttribute("errors", getActionErrors()); return INPUT; } return SUCCESS; } } </code></pre> Update 2: applicationContext-struts.xml: <pre><code><bean id="passwordHintAction" class="com.project.action.PasswordHintAction" scope="prototype"> <property name="userManager" ref="userManager"/> <property name="mailEngine" ref="mailEngine"/> <property name="mailMessage" ref="mailMessage"/> </bean> </code></pre>

11,759,225

3

null

2012-08-01 12:18:04.617 UTC

7

2020-12-31 10:47:19.61 UTC

2016-05-17 14:54:31.643 UTC

null

5,183,619

null

187,922

null

1

20

java|spring|hibernate|spring-mvc|struts

180,697

Use component scanning as given below, if <code>com.project.action.PasswordHintAction</code> is annotated with stereotype annotations <pre><code><context:component-scan base-package="com.project.action"/> </code></pre> EDIT I see your problem, in <code>PasswordHintActionTest</code> you are autowiring <code>PasswordHintAction</code>. But you did not create bean configuration for <code>PasswordHintAction</code> to autowire. Add one of stereotype annotation(<code>@Component, @Service, @Controller</code>) to <code>PasswordHintAction</code> like <pre><code>@Component public class PasswordHintAction extends BaseAction { private static final long serialVersionUID = -4037514607101222025L; private String username; </code></pre> or create xml configuration in <code>applicationcontext.xml</code> like <pre><code><bean id="passwordHintAction" class="com.project.action.PasswordHintAction" /> </code></pre>

11,575,943

Parse file name from URL before downloading the file

I'm downloading an ePub file from a URL. Now I want to implement a mechanism by which if user tries to re-download the same file, he should get warning/error message and that file should not be downloaded again. To implement this, I need to check the name of the file present in my library with the name of the file user is trying to download. But I just have <a href="http://dl.dropbox.com/u/1177388/flagship_july_4_2010_flying_island_press.epub">this download link</a>, and not the file name. How to get the name of the file before download in order to compare it with the existing file?

11,576,046

6

0

null

2012-07-20 08:46:32.083 UTC

13

2021-06-06 10:39:09.213 UTC

2012-07-20 09:27:27.823 UTC

null

1,061,728

null

1,061,728

null

1

41

android|download

43,441

In android you can use <a href="https://developer.android.com/reference/android/webkit/URLUtil.html#guessFileName(java.lang.String,%20java.lang.String,%20java.lang.String)" rel="noreferrer">the guessFileName() method</a>: <pre><code>URLUtil.guessFileName(url, null, null) </code></pre> Alternatively, a simplistic solution in Java could be: <pre><code>String fileName = url.substring(url.lastIndexOf('/') + 1); </code></pre> (Assuming your url is in the format: <code>http://xxxxxxxxxxxxx/filename.ext</code>) UPDATE March 23, 2018 This question is getting lots of hits and someone commented my 'simple' solution does not work with certain urls so I felt the need to improve the answer. In case you want to handle more complex url pattern, I provided a sample solution below. It gets pretty complex quite quickly and I'm pretty sure there are some odd cases my solution still can't handle but nevertheless here it goes: <pre><code>public static String getFileNameFromURL(String url) { if (url == null) { return ""; } try { URL resource = new URL(url); String host = resource.getHost(); if (host.length() > 0 && url.endsWith(host)) { // handle ...example.com return ""; } } catch(MalformedURLException e) { return ""; } int startIndex = url.lastIndexOf('/') + 1; int length = url.length(); // find end index for ? int lastQMPos = url.lastIndexOf('?'); if (lastQMPos == -1) { lastQMPos = length; } // find end index for # int lastHashPos = url.lastIndexOf('#'); if (lastHashPos == -1) { lastHashPos = length; } // calculate the end index int endIndex = Math.min(lastQMPos, lastHashPos); return url.substring(startIndex, endIndex); } </code></pre> This method can handle these type of input: <pre><code>Input: "null" Output: "" Input: "" Output: "" Input: "file:///home/user/test.html" Output: "test.html" Input: "file:///home/user/test.html?id=902" Output: "test.html" Input: "file:///home/user/test.html#footer" Output: "test.html" Input: "http://example.com" Output: "" Input: "http://www.example.com" Output: "" Input: "http://www.example.txt" Output: "" Input: "http://example.com/" Output: "" Input: "http://example.com/a/b/c/test.html" Output: "test.html" Input: "http://example.com/a/b/c/test.html?param=value" Output: "test.html" Input: "http://example.com/a/b/c/test.html#anchor" Output: "test.html" Input: "http://example.com/a/b/c/test.html#anchor?param=value" Output: "test.html" </code></pre> You can find the whole source code here: <a href="https://ideone.com/uFWxTL" rel="noreferrer">https://ideone.com/uFWxTL</a>

11,803,482

How to automatically FTP files that I am editing

I'm trying to figure out how to autoftp with Filezilla. Are there any other programs that do this right off the bat?

11,803,537

7

null

2012-08-03 21:23:13.347 UTC

11

2020-07-28 22:30:14.44 UTC

2017-02-15 13:37:33.997 UTC

null

4,477,659

null

1,549,397

null

1

42

windows|ftp|filezilla

91,811

If by "autoftp" you mean "update the file on the server whenever I save it" and you're working with code, then I'd recommend the wonderful <a href="http://notepad-plus-plus.org/">Notepad++</a>

11,738,823

Explicitly calling return in a function or not

A while back <a href="https://stackoverflow.com/questions/10412720/rserve-return-type-in-case-of-multiple-statements/10413020#10413020">I got rebuked</a> by Simon Urbanek from the R core team (I believe) for recommending a user to explicitly calling <code>return</code> at the end of a function (his comment was deleted though): <pre><code>foo = function() { return(value) } </code></pre> instead he recommended: <pre><code>foo = function() { value } </code></pre> Probably in a situation like this it is required: <pre><code>foo = function() { if(a) { return(a) } else { return(b) } } </code></pre> His comment shed some light on why not calling <code>return</code> unless strictly needed is a good thing, but this was deleted. My question is: Why is not calling <code>return</code> faster or better, and thus preferable?

11,834,490

9

4

null

2012-07-31 11:12:55.697 UTC

63

2020-07-23 11:22:35.037 UTC

2017-05-23 11:54:51.513 UTC

null

-1

null

1,033,808

null

1

225

r

116,297

Question was: Why is not (explicitly) calling return faster or better, and thus preferable? There is no statement in R documentation making such an assumption. The main page ?'function' says: <pre><code>function( arglist ) expr return(value) </code></pre> Is it faster without calling return? Both <code>function()</code> and <code>return()</code> are primitive functions and the <code>function()</code> itself returns last evaluated value even without including <code>return()</code> function. Calling <code>return()</code> as <code>.Primitive('return')</code> with that last value as an argument will do the same job but needs one call more. So that this (often) unnecessary <code>.Primitive('return')</code> call can draw additional resources. Simple measurement however shows that the resulting difference is very small and thus can not be the reason for not using explicit return. The following plot is created from data selected this way: <pre><code>bench_nor2 <- function(x,repeats) { system.time(rep( # without explicit return (function(x) vector(length=x,mode="numeric"))(x) ,repeats)) } bench_ret2 <- function(x,repeats) { system.time(rep( # with explicit return (function(x) return(vector(length=x,mode="numeric")))(x) ,repeats)) } maxlen <- 1000 reps <- 10000 along <- seq(from=1,to=maxlen,by=5) ret <- sapply(along,FUN=bench_ret2,repeats=reps) nor <- sapply(along,FUN=bench_nor2,repeats=reps) res <- data.frame(N=along,ELAPSED_RET=ret["elapsed",],ELAPSED_NOR=nor["elapsed",]) # res object is then visualized # R version 2.15 </code></pre> <img src="https://i.stack.imgur.com/qNjIS.png" alt="Function elapsed time comparison"> The picture above may slightly difffer on your platform. Based on measured data, the size of returned object is not causing any difference, the number of repeats (even if scaled up) makes just a very small difference, which in real word with real data and real algorithm could not be counted or make your script run faster. Is it better without calling return? <code>Return</code> is good tool for clearly designing "leaves" of code where the routine should end, jump out of the function and return value. <pre><code># here without calling .Primitive('return') > (function() {10;20;30;40})() [1] 40 # here with .Primitive('return') > (function() {10;20;30;40;return(40)})() [1] 40 # here return terminates flow > (function() {10;20;return();30;40})() NULL > (function() {10;20;return(25);30;40})() [1] 25 > </code></pre> It depends on strategy and programming style of the programmer what style he use, he can use no return() as it is not required. R core programmers uses both approaches ie. with and without explicit return() as it is possible to find in sources of 'base' functions. Many times only return() is used (no argument) returning NULL in cases to conditially stop the function. It is not clear if it is better or not as standard user or analyst using R can not see the real difference. My opinion is that the question should be: Is there any danger in using explicit return coming from R implementation? Or, maybe better, user writing function code should always ask: What is the effect in not using explicit return (or placing object to be returned as last leaf of code branch) in the function code?

20,147,081

Javascript - catch access to property of object

Is it possible to capture when a (any) property of an object is accessed, or attempting to be accessed? Example: I have created custom object <code>Foo</code> <pre><code>var Foo = (function(){ var self = {}; //... set a few properties return self; })(); </code></pre> Then there is some action against <code>Foo</code> - someone tries to access property <code>bar</code> <pre><code>Foo.bar </code></pre> Is there way (prototype, perhaps) to capture this? <code>bar</code> may be undefined on <code>Foo</code>. I could suffice with capturing any attempted access to undefined properties. For instance, if <code>bar</code> is undefined on <code>Foo</code>, and <code>Foo.bar</code> is attempted, something like: <pre><code>Foo.prototype.undefined = function(){ var name = this.name; //name of property they attempted to access (bar) Foo[name] = function(){ //...do something }; return Foo[name]; } </code></pre> But functional, unlike my example. Concept <pre><code>Foo.* = function(){ } </code></pre> Background If I have a custom function, I can listen for every time this function is called (see below). Just wondering if it's possible with property access. <pre><code>Foo = function(){}; Foo.prototype.call = function(thisArg){ console.log(this, thisArg); return this; } </code></pre>

20,147,219

5

null

2013-11-22 14:19:00.357 UTC

10

2019-09-24 06:52:12.877 UTC

2013-11-22 14:27:42.673 UTC

null

1,750,282

null

1,750,282

null

1

27

javascript|object-properties

12,453

Yes, this is possible in ES2015+, using the <a href="http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies" rel="noreferrer">Proxy</a>. It's not possible in ES5 and earlier, not even with polyfills. It took me a while, but I finally found <a href="https://stackoverflow.com/questions/7891937/is-it-possible-to-implement-dynamic-getters-setters-in-javascript/7891968#7891968">my previous answer</a> to this question. See that answer for all the details on proxies and such. Here's the proxy example from that answer: <pre><code>const obj = new Proxy({}, { get: function(target, name, receiver) { if (!(name in target)) { console.log("Getting non-existant property '" + name + "'"); return undefined; } return Reflect.get(target, name, receiver); }, set: function(target, name, value, receiver) { if (!(name in target)) { console.log("Setting non-existant property '" + name + "', initial value: " + value); } return Reflect.set(target, name, value, receiver); } }); console.log("[before] obj.foo = " + obj.foo); obj.foo = "bar"; console.log("[after] obj.foo = " + obj.foo); obj.foo = "baz"; console.log("[after] obj.foo = " + obj.foo); </code></pre> Live Copy: <div class="snippet" data-lang="js" data-hide="true" data-console="true" data-babel="false"> <div class="snippet-code snippet-currently-hidden"> <pre class="snippet-code-js lang-js prettyprint-override"><code>"use strict"; const obj = new Proxy({}, { get: function(target, name, receiver) { if (!(name in target)) { console.log("Getting non-existant property '" + name + "'"); return undefined; } return Reflect.get(target, name, receiver); }, set: function(target, name, value, receiver) { if (!(name in target)) { console.log("Setting non-existant property '" + name + "', initial value: " + value); } return Reflect.set(target, name, value, receiver); } }); console.log("[before] obj.foo = " + obj.foo); obj.foo = "bar"; console.log("[after] obj.foo = " + obj.foo); obj.foo = "baz"; console.log("[after] obj.foo = " + obj.foo);</code></pre> </div> </div> When run, that outputs: <pre>Getting non-existant property 'foo' [before] obj.foo = undefined Setting non-existant property 'foo', initial value: bar [after] obj.foo = bar [after] obj.foo = baz</pre>

19,997,146

Kitkat kills: Not allowed to load local resource: file:///android_asset/webkit/android-weberror.png

I have an app that uses WebViews. I've changed my targetAPI from 18 to 19 and I'm currently testing on the new 4.4. For some reason I'm getting this error: <code>Not allowed to load local resource: file:///android_asset/webkit/android-weberror.png</code> on 4.4 but not on 4.3, does somebody have clue why? Since I don't really know where to start looking I can't give the complete code. It might have something to do with the <code>shouldInterceptRequest(Webview, String)</code> method in the WebViewClient but I'm not really sure. If I know more, I'll update the question.

20,003,398

9

5

null

2013-11-15 09:01:27.803 UTC

10

2022-09-15 05:55:44.527 UTC

null

1,388,116

null

1

27

android|android-webview

47,835

"Not allowed to load local resource" is a security origin error. The KitKat WebView has stronger security restrictions and it seems like these are kicking in. FWIW I tried just loading a file:///android_asset URL and it worked fine. Did you call any of the file-related WebSettings APIs (like setAllowFileAccess(false)) by any chance? Are you trying to load the resource from an https: URL?

3,730,053

How to delete all databases on Postgres?

I take daily backs of our postgres development box using: pg_dumpall -h 127.0.0.1 -U user -w | gzip blah.gz Since 9.0 is now a release candidate I would like to restore this daily backup on a daily basis to a postgres9.0rc1 box for testing, however I'm not sure how to script it repeatedly. Is there some directory I can nuke to do this?

58,735,470

5

0

null

2010-09-16 19:28:20.293 UTC

10

2022-07-11 09:48:15.353 UTC

null

160,208

null

1

27

postgresql

67,780

Granted the question is 9 years old at this point, but it's still the second google result for deleting all databases. If you just want to go from N DBs to 0 without jacking with your config and also having rummage through the file system, this is a much better answer: <a href="https://stackoverflow.com/a/24548640/3499424">https://stackoverflow.com/a/24548640/3499424</a> From the answer, the following script will generate N <code>drop database</code> commands, one for each non-template DB: <pre class="lang-sql prettyprint-override"><code>select 'drop database "'||datname||'";' from pg_database where datistemplate=false; </code></pre> From there, you can edit and run manually, or pipe further along into a script. Here's a somewhat verbose one-liner: <code>echo \pset pager off \copy (select 'drop database "'||datname||'";' from pg_database where datistemplate=false) to STDOUT; | psql -U <user> -d postgres | <appropriate grep> | psql -U <user> -d postgres</code> Explanation: <ol> <li>This is a series of pipes</li> <li><code>echo \pset pager off \copy (select 'drop database "'||datname||'";' from pg_database where datistemplate=false) to STDOUT;</code> generates a string for psql to execute <ol> <li><code>\pset pager off</code> ensures you get all records instead of that (54 rows) crap</li> <li><code>\copy (select 'drop database "'||datname||'";' from pg_database where datistemplate=false) to STDOUT;</code> executes the aforementioned query, sending the result to STDOUT. We have to do this since we lead with <code>\pset</code>.</li> </ol></li> <li><code>| psql -U <user> -d postgres</code> pipes said string into psql, which executes it. Replace <code><user></code> with the user you want to use</li> <li><code>| <appropriate grep></code> is for stripping out the "Pager usage is off" line <ol> <li>Windows users can use <code>findstr /v "Pager"</code> or <code>findstr /b "drop"</code></li> <li>*nix users can use <code>grep 'drop'</code></li> </ol></li> <li><code>| psql -U <user> -d postgres</code> pipes the resulting set of <code>drop database</code> commands into psql again, which executes them, thus dropping all the databases</li> <li>WARNING: Without any additional filtering, this will also drop the <code>postgres</code> database. You can strip it either in the <code>SELECT</code> or the grep if you don't want that to happen.</li> </ol>

3,461,869

Plot a plane based on a normal vector and a point in Matlab or matplotlib

How would one go plotting a plane in matlab or matplotlib from a normal vector and a point?

3,461,941

5

0

null

2010-08-11 19:05:03.433 UTC

19

2017-04-17 09:00:14.973 UTC

2017-02-17 08:30:40.697 UTC

null

656,804

null

319,988

null

1

38

matlab|matplotlib|plot|scipy

70,218

For Matlab: <pre><code>point = [1,2,3]; normal = [1,1,2]; %# a plane is a*x+b*y+c*z+d=0 %# [a,b,c] is the normal. Thus, we have to calculate %# d and we're set d = -point*normal'; %'# dot product for less typing %# create x,y [xx,yy]=ndgrid(1:10,1:10); %# calculate corresponding z z = (-normal(1)*xx - normal(2)*yy - d)/normal(3); %# plot the surface figure surf(xx,yy,z) </code></pre> <img src="https://i.stack.imgur.com/E80Ov.png" alt="enter image description here"> Note: this solution only works as long as normal(3) is not 0. If the plane is parallel to the z-axis, you can rotate the dimensions to keep the same approach: <pre><code>z = (-normal(3)*xx - normal(1)*yy - d)/normal(2); %% assuming normal(3)==0 and normal(2)~=0 %% plot the surface figure surf(xx,yy,z) %% label the axis to avoid confusion xlabel('z') ylabel('x') zlabel('y') </code></pre>

3,654,144

Direct "rate in iTunes" link in my app?

I've seen posts here on Stackoverflow that describe how to allow users to be directed to apps on the app store. Is there a way to link directly to the rating and comments form in the App Store?

20,788,267

5

null

2010-09-06 20:31:52.393 UTC

46

2018-09-04 12:40:06.64 UTC

2010-09-06 21:19:23.733 UTC

null

224,988

null

224,988

null

1

58

iphone|ios|hyperlink|rating|itunes-store

33,170

Answers here are outdated. This works on my end (Xcode 5 - iOS 7 - works only on Device, not simulator!): <pre><code>itms-apps://itunes.apple.com/app/idYOUR_APP_ID </code></pre> For versions lower than iOS 7 use the old one: <pre><code>itms-apps://itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?type=Purple+Software&id=YOUR_APP_ID </code></pre>

3,545,183

How to add an object into another Object set

I have two classes. One(Person) for getters and setters, and another(People) for compute the data. What is my situation is, I get the data from the DB using <code>ResultSet</code>, then created a person Object to store the row data. Then i created people Object to store all persons. Each Object created as SET. <pre><code>while(rs.next()) { Set<People> people = new HashSet<people>(); Person person = new Person(); String name = rs.getString(2); person.setName(name); int id = rs.getInt(1); person.setId(id); String dept = rs.getString(4); person.setDept(dept); int age = rs.getInt(3); person.setAge(age); people.add(person); } return people; </code></pre> Now the problem is the last line in the While Loop <code>people.add(person);</code> It says <blockquote> The method add(People) in the type Set is not applicable for the arguments (Person) </blockquote> How can i overcome this problem? Thanks.

3,545,247

6

0

null

2010-08-23 06:34:43.293 UTC

1

2018-02-18 14:35:37.057 UTC

2010-08-23 06:43:08.093 UTC

null

105,224

user405398

null

1

4

java|object|set

41,607

My understandig from your design is that you have a People has-many Person relation, so the <code>People</code> class holds a collection of <code>Person</code> objects. Then I'd expect something like this: <pre><code>public class Person { private String name; private Date dateOfBirth; // .. more attributes // getters and setters // overrides of equals, hashcode and toString } public class People implements Set<Person> { private Set<Person> persons = new HashSet<Person>(); public boolean add(Person person) { return persons.add(person); } // more methods for remove, contains, ... } </code></pre> So in your database related code you wouldn't need to create another set, because <code>People</code> already has the one you need: <pre><code>People people = new People(); // or get it, if it's already created while(rs.next()) { Person person = new Person(); String name = rs.getString(2); person.setName(name); int id = rs.getInt(1); person.setId(id); String dept = rs.getString(4); person.setDept(dept); int age = rs.getInt(3); person.setAge(age); people.add(person); } return people; </code></pre>

3,366,529

Wrap every 3 divs in a div

Is it possible to use <code>nth-child</code> selectors to wrap 3 divs using <code>.wrapAll</code>? I can't seem to work out the correct equation. so... <pre><code><div> <div></div> <div></div> <div></div> <div></div> <div></div> <div></div> </div> </code></pre> becomes... <pre><code><div> <div class="new"> <div></div> <div></div> <div></div> </div> <div class="new"> <div></div> <div></div> <div></div> </div> </div> </code></pre>

3,366,539

6

1

null

2010-07-29 20:09:11.187 UTC

37

2016-03-17 09:10:26.133 UTC

null

1,287,812

null

392,402

null

1

87

jquery|css-selectors|wrapall

64,965

You can do it with <a href="http://api.jquery.com/slice/" rel="noreferrer"><code>.slice()</code></a>, like this: <pre><code>var divs = $("div > div"); for(var i = 0; i < divs.length; i+=3) { divs.slice(i, i+3).wrapAll("<div class='new'></div>"); } </code></pre> <a href="http://jsfiddle.net/nick_craver/vmdaM/" rel="noreferrer">You can try out a demo here</a>, all we're doing here is getting the elements you want to wrap and looping through them, doing a <a href="http://api.jquery.com/wrapAll/" rel="noreferrer"><code>.wrapAll()</code></a> in batches of 3 then moving to the next 3, etc. It will wrap 3 at a time and however many are left at the end, e.g. 3, 3, 3, 2 if that's the case.

3,827,567

How to get the path of the batch script in Windows?

I know that <code>%0</code> contains the full path of the batch script, e.g. <code>c:\path\to\my\file\abc.bat</code> I would <code>path</code> to be equal to <code>c:\path\to\my\file</code> How could I achieve that ?

3,827,582

7

4

null

2010-09-30 03:46:52.24 UTC

84

2020-11-09 09:00:14.357 UTC

2017-03-07 09:40:25.963 UTC

null

27,423

null

247,243

null

1

406

windows|batch-file

416,150

<code>%~dp0</code> will be the directory. <a href="https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/call#batch-parameters" rel="noreferrer">Here's some documentation on all of the path modifiers</a>. Fun stuff :-) To remove the final backslash, you can use the <code>:n,m</code> substring syntax, like so: <pre><code>SET mypath=%~dp0 echo %mypath:~0,-1% </code></pre> I don't believe there's a way to combine the <code>%0</code> syntax with the <code>:~n,m</code> syntax, unfortunately.

3,559,419

Is there any Rails function to check if a partial exists?

When I render a partial which does not exists, I get an Exception. I'd like to check if a partial exists before rendering it and in case it doesn't exist, I'll render something else. I did the following code in my .erb file, but I think there should be a better way to do this: <pre><code> <% begin %> <%= render :partial => "#{dynamic_partial}" %> <% rescue ActionView::MissingTemplate %> Can't show this data! <% end %> </code></pre>

8,180,410

8

1

null

2010-08-24 17:51:32.407 UTC

17

2021-09-21 22:08:42.25 UTC

null

105,514

null

1

102

ruby-on-rails|partial

33,610

Currently, I'm using the following in my Rails 3/3.1 projects: <pre><code>lookup_context.find_all('posts/_form').any? </code></pre> The advantage over other solutions I've seen is that this will look in all view paths instead of just your rails root. This is important to me as I have a lot of rails engines. This also works in Rails 4.

8,028,737

how to do a relative path redirection using javascript?

I'm working on javascript/jquery in a php based site, and I have to redirect the page upon an event in the page. lets say, on clicking the button "click me" in <code>"page1.php"</code>, the page should be redirected to "<code>page2.php</code>". This redirection has to be done using javascript/ jquery. Both pages are in the same folder, and the redirection code should use 'RELATIVE LINKS'. Now, I am able to redirect if I give the absolute link to <code>page2.php</code>, but could someone let me know how to do the same with a relative link? something like: <pre><code>window.location.href = 'page2.php'; </code></pre> thanks.

8,028,848

4

5

null

2011-11-06 17:07:45.293 UTC

4

2014-05-06 20:00:01.117 UTC

2011-11-06 17:27:32.043 UTC

null

592,495

null

743,243

null

1

23

javascript|jquery

91,652

<pre><code>window.location.href = "page2.php"; </code></pre> this worked. Infact, relative and absolute works in the same way: <pre><code>window.location.href = "http://www.google.com"; // or window.location.href = "page2.html"; </code></pre>

7,883,916

Django filter the model on ManyToMany count?

Suppose I have something like this in my models.py: <pre><code>class Hipster(models.Model): name = CharField(max_length=50) class Party(models.Model): organiser = models.ForeignKey() participants = models.ManyToManyField(Profile, related_name="participants") </code></pre> Now in my views.py I would like to do a query which would fetch a party for the user where there are more than 0 participants. Something like this maybe: <pre><code>user = Hipster.get(pk=1) hip_parties = Party.objects.filter(organiser=user, len(participants) > 0) </code></pre> What's the best way of doing it?

7,884,061

5

0

null

2011-10-25 02:01:26.817 UTC

8

2022-06-14 23:26:50.34 UTC

null

672,226

null

1

82

django|django-models|django-queryset

24,394

If this works this is how I would do it. Best way can mean a lot of things: best performance, most maintainable, etc. Therefore I will not say this is the best way, but I like to stick to the ORM features as much as possible since it seems more maintainable. <pre><code>from django.db.models import Count user = Hipster.objects.get(pk=1) hip_parties = (Party.objects.annotate(num_participants=Count('participants')) .filter(organiser=user, num_participants__gt=0)) </code></pre>

14,549,489

How to fix pure virtual function called runtime error?

I understand why I am getting the error I am getting (pure virtual function called). I am trying to call pure virtual functions from within the destructor of my base class shown below. However, I do not know how to rework my code to prevent this from happening. Here are the base and derived classes (the relevant portions anyway): Base class: <pre><code>TailFileManager::TailFileManager(const std::string &filename, const int fileOpenPeriod_ms) : m_Stop(false) { m_WorkerThread.reset(new boost::thread(boost::bind(&TailFileManager::TailFile, this, filename, fileOpenPeriod_ms))); } TailFileManager::~TailFileManager() { m_Stop = true; m_WorkerThread->join(); } void TailFileManager::TailFile(const std::string &filename, const int fileOpenPeriod_ms) { std::ifstream ifs(filename.c_str()); while (! ifs.is_open()) { boost::this_thread::sleep(boost::posix_time::milliseconds(fileOpenPeriod_ms)); ifs.open(filename.c_str()); } ifs.seekg(0, std::ios::end); while (! m_Stop) { ifs.clear(); std::string line; while (std::getline(ifs, line)) { OnLineAdded(line); } OnEndOfFile(); } ifs.close(); } </code></pre> Derived class: <pre><code>ETSLogTailFileManager::ETSLogTailFileManager(const std::string &filename, const int heartbeatPeriod_ms) : TailFileManager(filename, heartbeatPeriod_ms), m_HeartbeatPeriod_ms(heartbeatPeriod_ms), m_FoundInboundMessage(false), m_TimeOfLastActivity(0) { } ETSLogTailFileManager::~ETSLogTailFileManager() { } void ETSLogTailFileManager::OnLineAdded(const std::string &line) { // do stuff... } void ETSLogTailFileManager::OnEndOfFile() { // do stuff... } </code></pre>

14,549,689

4

13

null

2013-01-27 16:34:08.49 UTC

2

2021-10-27 10:45:28.417 UTC

2015-03-07 10:30:27.043 UTC

null

3,235,496

null

834,594

null

1

4

c++|pure-virtual

38,659

You shouldn't call virtual functions during construction or destruction, because the calls won't do what you think, and if they did, you'd still be unhappy. If you're a recovering Java or C# programmer, pay close attention to this Item, because this is a place where those languages zig, while C++ zags. Re-work your design i.e you may call some cleanup function before object get destroyed, idea is just avoid virtual function during const/dest (if there are any!), if you are working with C++... The rules for virtual invocation are different. C++ 2003, section 12.7 "Construction and Destruction", says: Lets refresh some old memories ... Member functions, including virtual functions (10.3), can be called during construction or destruction (12.6.2). When a virtual function is called directly or indirectly from a constructor (including from the mem-initializer for a data member) or from a destructor, and the object to which the call applies is the object under construction or destruction, the function called is the one defined in the constructor or destructorâs own class or in one of its bases, but not a function overriding it in a class derived from the constructor or destructorâs class, or overriding it in one of the other base classes of the most derived object (1.8). If the virtual function call uses an explicit class member access (5.2.5) and the object-expression refers to the object under construction or destruction but its type is neither the constructor or destructorâs own class or one of its bases, the result of the call is undefined. Because of this difference in behavior, it is recommended that you never invoke an object's virtual function while it is being constructed or destroyed. Never Call Virtual Functions during Construction or Destruction An Excerpt from Effective C++, Third Edition by Scott Meyers June 6, 2005 <a href="http://www.artima.com/cppsource/nevercall.html" rel="noreferrer">http://www.artima.com/cppsource/nevercall.html</a>

14,739,537

Convert plain text in to HTML

I have a script with which at a certain point I'm getting HTML(data) with Ajax call. I have to turn this HTML in to plain text like this: <pre><code>$("#div").text(data); </code></pre> I now want to turn this around and make the text HTML again. I there an easy Jquery method of doing this? I tried: <pre><code>$("#div").text(data).end().html(); </code></pre> No luck.

14,739,598

5

9

null

2013-02-06 21:52:57.79 UTC

3

2016-03-21 07:04:09.35 UTC

null

647,909

null

1

6

jquery|text

54,863

You would need to hold onto the original response to do this... <pre><code>$("#hiddendiv").html(data); $("#div").text(data); </code></pre> Then you could get it back out... <pre><code>var html = $("#hiddendiv").html(); </code></pre> Update based on comment... You can remove that element before you display it... <pre><code>var html = $(data); $('#cookiediv', html).hide(); $('#div').html(html); </code></pre> Where the cookie message has <code>id="cookiediv"</code> - you may need to adjust the selector to get to this div, but it is almost certainly possible to grab it.

4,378,455

What is the complexity of regular expression?

What is the complexity with respect to the string length that takes to perform a regular expression comparison on a string?

4,378,626

4

3

null

2010-12-07 15:38:56.67 UTC

23

2019-03-21 15:11:04.427 UTC

null

132,640

null

1

85

regex|complexity-theory|big-o

47,258

The answer depends on what exactly you mean by "regular expressions." Classic regexes can be <a href="http://lambda.uta.edu/cse5317/spring01/notes/node9.html" rel="noreferrer">compiled</a> into <a href="http://en.wikipedia.org/wiki/Deterministic_finite-state_machine" rel="noreferrer">Deterministic Finite Automata</a> that can match a string of length <code>N</code> in <code>O(N)</code> time. Certain extensions to the regex language change that for the worse. You may find the following document of interest: <a href="http://swtch.com/~rsc/regexp/regexp1.html" rel="noreferrer">Regular Expression Matching Can Be Simple And Fast</a>.

4,582,562

How can I add commas to numbers in PHP

I would like to know how can I add comma's to numbers. To make my question simple. I would like to change this: <pre><code>1210 views </code></pre> To: <pre><code>1,210 views </code></pre> and : <pre><code>14301 </code></pre> to <pre><code>14,301 </code></pre> and so on for larger numbers. Is it possible with a php function?

4,582,575

6

0

null

2011-01-03 06:49:01.96 UTC

10

2022-05-12 08:07:21.877 UTC

2011-03-26 00:10:03.443 UTC

null

385,273

null

77,762

null

1

72

php

103,881

from the php manual <a href="http://php.net/manual/en/function.number-format.php" rel="noreferrer">http://php.net/manual/en/function.number-format.php</a> I'm assuming you want the english format. <pre><code><?php $number = 1234.56; // english notation (default) $english_format_number = number_format($number); // 1,235 // French notation $nombre_format_francais = number_format($number, 2, ',', ' '); // 1 234,56 $number = 1234.5678; // english notation with a decimal point and without thousands seperator $english_format_number = number_format($number, 2, '.', ''); // 1234.57 ?> </code></pre> my 2 cents

4,100,022

php validate integer

I`m wonder why this not working <pre><code> echo gettype($_GET['id']); //returns string if(is_int($_GET['id'])) { echo 'Integer'; } </code></pre> How to validate data passing from GET/POST if it is integer ?

4,100,065

7

0

null

2010-11-04 18:37:51.163 UTC

8

2015-01-19 17:58:59.73 UTC

null

497,577

null

1

20

php

40,917

The <a href="http://php.net/manual/en/function.is-int.php" rel="noreferrer">manual</a> says: <blockquote> To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric(). </blockquote> Alternative you can use the regex based test as: <pre><code>if(preg_match('/^\d+$/',$_GET['id'])) { // valid input. } else { // invalid input. } </code></pre>

4,742,210

implementing debounce in Java

For some code I'm writing I could use a nice general implementation of <code>debounce</code> in Java. <pre><code>public interface Callback { public void call(Object arg); } class Debouncer implements Callback { public Debouncer(Callback c, int interval) { ... } public void call(Object arg) { // should forward calls with the same arguments to the callback c // but batch multiple calls inside `interval` to a single one } } </code></pre> When <code>call()</code> is called multiple times in <code>interval</code> milliseconds with the same argument the callback function should be called exactly once. A visualization: <pre><code>Debouncer#call xxx x xxxxxxx xxxxxxxxxxxxxxx Callback#call x x x (interval is 2) </code></pre> <ul> <li>Does (something like) this exist already in some Java standard library?</li> <li>How would you implement that?</li> </ul>

20,978,973

9

2

null

2011-01-20 00:10:10.453 UTC

11

2021-06-04 09:26:15.343 UTC

null

55,534

null

1

29

java|algorithm

24,372

Please consider the following thread safe solution. Note that the lock granularity is on the key level, so that only calls on the same key block each other. It also handles the case of an expiration on key K which occurs while call(K) is called. <pre><code>public class Debouncer <T> { private final ScheduledExecutorService sched = Executors.newScheduledThreadPool(1); private final ConcurrentHashMap<T, TimerTask> delayedMap = new ConcurrentHashMap<T, TimerTask>(); private final Callback<T> callback; private final int interval; public Debouncer(Callback<T> c, int interval) { this.callback = c; this.interval = interval; } public void call(T key) { TimerTask task = new TimerTask(key); TimerTask prev; do { prev = delayedMap.putIfAbsent(key, task); if (prev == null) sched.schedule(task, interval, TimeUnit.MILLISECONDS); } while (prev != null && !prev.extend()); // Exit only if new task was added to map, or existing task was extended successfully } public void terminate() { sched.shutdownNow(); } // The task that wakes up when the wait time elapses private class TimerTask implements Runnable { private final T key; private long dueTime; private final Object lock = new Object(); public TimerTask(T key) { this.key = key; extend(); } public boolean extend() { synchronized (lock) { if (dueTime < 0) // Task has been shutdown return false; dueTime = System.currentTimeMillis() + interval; return true; } } public void run() { synchronized (lock) { long remaining = dueTime - System.currentTimeMillis(); if (remaining > 0) { // Re-schedule task sched.schedule(this, remaining, TimeUnit.MILLISECONDS); } else { // Mark as terminated and invoke callback dueTime = -1; try { callback.call(key); } finally { delayedMap.remove(key); } } } } } </code></pre> and callback interface: <pre><code>public interface Callback<T> { public void call(T t); } </code></pre>

4,749,585

What is the meaning of XOR in x86 assembly?

I'm getting into assembly and I keep running into xor, for example: <pre><code>xor ax, ax </code></pre> Does it just clear the register's value?

4,749,620

11

2

null

2011-01-20 16:14:22.763 UTC

13

2016-02-01 06:25:45.047 UTC

2015-07-08 15:08:56.12 UTC

null

895,245

null

362,857

null

1

51

assembly|xor

112,422

<code>A XOR B</code> in english would be translated as "are A and B not equal". So <code>xor ax, ax</code> will set <code>ax</code> to zero since ax is always equal to itself. <pre><code>A B | A XOR B 0 0 | 0 1 0 | 1 0 1 | 1 1 1 | 0 </code></pre>

14,695,805

How to print everything from an struct array in c++?

I have a structured a data type called bookStruct and books is the name of the variable associated with the bookStruct data type. book[10] is the array that is 10 characters long and has 4 characters of data, meaning book[0] to book [3] have datas in them when the rest are empty (o values). Now I want to print the datas that are availabe already in the array and not print the ones that are empty otherwise 0. I tried the below code, with no luck.What am I doing wrong here? <pre><code>for (int i=0;i<MAX_BOOKS && books[i]!='\0';i++) { cout << "Book Title: " << books[i].bookTitle << endl; cout << "Total Pages: " << books[i].bookPageN << endl; cout << "Book Review: " << books[i].bookReview << endl; cout << "Book Price: " << books[i].bookPrice<< "\n\n" << endl; } </code></pre> here is the declaration for book struct <pre><code>struct bookStruct { string bookTitle; int bookPageN; int bookReview; float bookPrice; }; bookStruct books[10]; </code></pre>

14,695,932

3

14

null

2013-02-04 21:16:52.04 UTC

2

2022-07-28 06:00:09.88 UTC

2013-02-04 21:25:10.903 UTC

user2017078

null

user2017078

null

1

8

c++|struct

47,399

It's a little hard to tell what's being asked here. You see, it's quite easy to just keep count of how many books you have stored: <pre><code>int numBooks = 0; </code></pre> When you add a book, you increment <code>numBooks</code> up until <code>MAX_BOOKS</code>. <pre><code>for( int i=0; i<numBooks; i++ ) ... </code></pre> If you don't want to do that, you certainly can't test <code>books[i] != '\0'</code> because that is testing the struct against a single character. Instead, you might want to test <code>books[i].bookTitle.size() != 0</code> (or indeed <code>!books[i].bookTitle.empty()</code>). <pre><code>for( int i=0; i<MAX_BOOKS && !books[i].bookTitle.empty(); i++ ) ... </code></pre> Another alternative is to store books in a <code>vector</code> instead of an array, so you don't have to worry about maximum counts and current counts. The vector can shrink and grow for you. <pre><code>vector<bookStruct> books; ... for( int i = 0; i < books.size(); i++ ) ... </code></pre>

14,601,430

How to run a c program in bash script and give it 2 arguments?

I have a program in C, which takes 2 arguments, filename and text. I want to write a script in bash, which also take 2 arguments, path and file extension, will iterate through all files in given path and give to my program in C as argument files with the givenextension only and text. Heres my program in C, nothing special really: <pre><code>#include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { if(argc < 3) { fprintf(stderr, "Give 2 args!\n"); exit(-1); } char *arg1 = argv[1]; char *arg2 = argv[2]; fprintf(stdout, "You gave: %s, %s\n", arg1, arg2); return 0; } </code></pre> and my bash script: <pre><code>#!/bin/bash path=$1 ext=$2 text=$3 for file in $path/*.$ext do ./app | { echo $file echo $text } done </code></pre> I use it like this: <code>./script /tmp txt hello</code> and it should give as arguments all <code>txt</code> files from <code>/tmp</code> and 'hello' as text to my C program. No it only shows <code>Give 2 args!</code> :( Please, help.

14,601,483

3

0

null

2013-01-30 10:13:23.583 UTC

1

2013-01-30 10:15:57.037 UTC

null

1,612,090

null

1

8

c|bash|shell

42,300

Right now you're not actually passing any arguments to the program in your script. Just pass the arguments normally: <pre><code>./app "$file" "$text" </code></pre> I put the arguments in double-quotes to make the shell see the variables as single arguments, in case they contain spaces.

14,446,951

How to intercept and manipulate a Internet Explorer popup with VBA

Language/Software: The language is VBA. The application is Access 2003 (I also can use Excel) and Internet Explorer (on Windows XP/Seven). The problem: I'm developing a Access macro which opens and manipulates a intranet site of the enterprise where I work. I can create new IE windows and fill data in the forms, but I need to be able of intercept and manipulate other IE windows, such as popups, which opens when I click on a link, when I choose an option of a select element or when the page is loaded.

14,470,224

1

4

null

2013-01-21 20:47:46.08 UTC

8

2017-06-19 13:05:45.37 UTC

2014-02-07 09:15:25.86 UTC

null

2,060,725

null

1,720,294

null

1

10

internet-explorer|vba|dom|automation|popup

33,617

Here's some code I use to get an IE window from it's title. It's split into two functions because one of my users was having an extremely odd problem where an error was not being caught properly. You might (probably will) be able to move the body of the private function into the public function. Additionally, you'll need to set a reference to Microsoft Internet Controls (this is either shdocvw.dll or ieframe.dll, depending on your version of Windows) and I'd recommend setting a reference to Microsoft HTML Object Library to make it easier to traverse the DOM once you have your IE object. <pre><code>Function oGetIEWindowFromTitle(sTitle As String, _ Optional bCaseSensitive As Boolean = False, _ Optional bExact As Boolean = False) As SHDocVw.InternetExplorer Dim objShellWindows As New SHDocVw.ShellWindows Dim found As Boolean Dim startTime As Single found = False 'Loop through shell windows For Each oGetIEWindowFromTitle In objShellWindows found = oGetIEWindowFromTitleHandler(oGetIEWindowFromTitle, sTitle, bCaseSensitive, bExact) If found Then Exit For Next 'Check whether a window was found If Not found Then Set oGetIEWindowFromTitle = Nothing Else pauseUntilIEReady oGetIEWindowFromTitle End If End Function Private Function oGetIEWindowFromTitleHandler(win As SHDocVw.InternetExplorer, _ sTitle As String, _ bCaseSensitive As Boolean, _ bExact As Boolean) As Boolean oGetIEWindowFromTitleHandler = False On Error GoTo handler 'If the document is of type HTMLDocument, it is an IE window If TypeName(win.Document) = "HTMLDocument" Then 'Check whether the title contains the passed title If bExact Then If (win.Document.title = sTitle) Or ((Not bCaseSensitive) And (LCase(sTitle) = LCase(win.Document.title))) Then oGetIEWindowFromTitleHandler = True Else If InStr(1, win.Document.title, sTitle) Or ((Not bCaseSensitive) And (InStr(1, LCase(win.Document.title), LCase(sTitle), vbTextCompare) <> 0)) Then oGetIEWindowFromTitleHandler = True End If End If handler: 'We assume here that if an error is raised it's because 'the window is not of the correct type. Therefore we 'simply ignore it and carry on. End Function </code></pre> Use the above code as follows: <pre><code>Sub test() Dim ie As SHDocVw.InternetExplorer Dim doc As HTMLDocument 'If you have a reference to the HTML Object Library 'Dim doc as Object 'If you do not have a reference to the HTML Object Library ' Change the title here as required Set ie = oGetIEWindowFromTitle("My popup window") Set doc = ie.Document Debug.Print doc.getElementsByTagName("body").Item(0).innerText End Sub </code></pre> You can find a window from almost any property of the window, or it's document contents. If you're struggling with this, please comment :).

14,413,404

C# for loop increment by 2 trouble

This algorithm is about to store strings from Array A to Array B by storing "A", "B" to Index 8 and Index 9 I really initiate to make the array size of B to be 10 because later I will put some other things there. My partial code: <pre><code>string[] A = new string[]{"A","B"} string[] B = new string[10]; int count; for(count = 0; count < A.length; count++) { B[count] = A[count] } </code></pre>

14,413,535

2

3

null

2013-01-19 10:33:06.763 UTC

1

2016-07-27 16:18:22.723 UTC

null

2,256,028

null

1,944,787

null

1

13

c#-4.0

81,931

So you want to increment every index with 2: <pre><code>string[] A = new string[] { "A", "B", "C", "D" }; string[] B = new string[A.Length + 2]; for (int i = 0; i < A.Length; i++) { B[i + 2] = A[i]; } </code></pre> <a href="http://ideone.com/8brFRU">Demo</a> <pre><code>Index: 0 Value: Index: 1 Value: Index: 2 Value: A Index: 3 Value: B Index: 4 Value: C Index: 5 Value: D </code></pre> Edit: So you want to start with index 0 in B and always leave a gap? <pre><code>string[] A = new string[] { "A", "B", "C", "D" }; string[] B = new string[A.Length * 2 + 2]; // you wanted to add something other as well for (int i = 0; i/2 < A.Length; i+=2) { B[i] = A[i / 2]; } </code></pre> <a href="http://ideone.com/fZy4yz">Demo</a> <pre><code>Index: 0 Value: A Index: 1 Value: Index: 2 Value: B Index: 3 Value: Index: 4 Value: C Index: 5 Value: Index: 6 Value: D Index: 7 Value: Index: 8 Value: Index: 9 Value: </code></pre> Update " Is there any alternative coding aside from this?" You can use Linq, although it would be less readable and efficient than a simple loop: <pre><code>String[] Bs = Enumerable.Range(0, A.Length * 2 + 2) // since you want two empty places at the end .Select((s, i) => i % 2 == 0 && i / 2 < A.Length ? A[i / 2] : null) .ToArray(); </code></pre> Final Update according to your last comment(start with index 1 in B): <pre><code>for (int i = 1; (i-1) / 2 < A.Length; i += 2) { B[i] = A[(i-1) / 2]; } </code></pre> <a href="http://ideone.com/OWkZyz">Demo</a> <pre><code>Index: 0 Value: Index: 1 Value: A Index: 2 Value: Index: 3 Value: B Index: 4 Value: Index: 5 Value: C Index: 6 Value: Index: 7 Value: D Index: 8 Value: Index: 9 Value </code></pre>

14,746,497

How to add attributes to a label generated with Zend/Form in Zend framework 2

I'm adding forms to my page using Zend/Form. I'm adding elements by defining them as follows: <pre><code> $this->add(array( 'name' => 'value', 'attributes' => array( 'type' => 'text', 'id' => 'value', 'autocomplete' => 'off', 'placeholder' => 'Cost', ), 'options' => array( 'label' => 'Cost', ), )); </code></pre> As you can see there is a 'label' => 'cost' node, this generated a label to go with the input element. How do I add classes, attributes to this label ?

14,746,670

4

0

null

2013-02-07 08:14:45.703 UTC

8

2017-10-24 20:14:50.463 UTC

null

2,883,328

null

1,141,800

null

1

24

php|forms|zend-framework2|label|zend-form2

23,486

Please try this, i haven't tested or used this, but going by the source it should function properly: <pre><code>$this->add(array( 'name' => 'value', 'attributes' => array(), 'options' => array( 'label_attributes' => array( 'class' => 'mycss classes' ), // more options ), )); </code></pre> If this does not function, please leave me a comment. If it won't function, it is not possible using this approach, since the <code>FormLabel</code> restricts the <code>validAttributes</code> quite a bit: <pre><code>protected $validTagAttributes = array( 'for' => true, 'form' => true, ); </code></pre>

14,414,832

Why use initializer_list instead of vector in parameters?

What is the actual benefit and purpose of <code>initializer_list</code>, for unknown number of parameters? Why not just use <code>vector</code> and be done with it? In fact, it sounds like just a <code>vector</code> with another name. Why bother? The only "benefit" I see of <code>initializer_list</code> is that it has <code>const</code> elements, but that doesn't seem to be a reason enough to invent this whole new type. (You can just use a <code>const vector</code> after all.) So, what am I mising?

14,414,905

3

7

null

2013-01-19 13:26:13.83 UTC

20

2015-09-17 15:59:43.61 UTC

null

1,859,852

null

1

50

c++

20,169

It is a sort of contract between the programmer and the compiler. The programmer says <code>{1,2,3,4}</code>, and the compiler creates an object of type <code>initializer_list<int></code> out of it, containing the same sequence of elements in it. This contract is a requirement imposed by the language specification on the compiler implementation. That means, it is not the programmer who creates manually such an object but it is the compiler which creates the object, and pass that object to function which takes <code>initializer_list<int></code> as argument. The <code>std::vector</code> implementation takes advantage of this contract, and therefore it defines a constructor which takes <code>initializer_list<T></code> as argument, so that it could initialize itself with the elements in the initializer-list. Now suppose for a while that the <code>std::vector</code> doesn't have any constructor that takes <code>std::initializer_list<T></code> as argument, then you would get this: <pre><code> void f(std::initializer_list<int> const &items); void g(std::vector<int> const &items); f({1,2,3,4}); //okay g({1,2,3,4}); //error (as per the assumption) </code></pre> As per the assumption, since <code>std::vector</code> doesn't have constructor that takes <code>std::initializer_list<T></code> as argument, which implies you cannot pass <code>{1,2,3,4}</code> as argument to <code>g()</code> as shown above, because the compiler cannot create an instance of <code>std::vector</code> out of the expression <code>{1,2,3,4}</code> directly. It is because no such contract is ever made between programmer and the compiler, and imposed by the language. It is through <code>std::initializer_list</code>, the <code>std::vector</code> is able to create itself out of expression <code>{1,2,3,4}</code>. Now you will understand that <code>std::initializer_list</code> can be used wherever you need an expression of the form of <code>{value1, value2, ...., valueN}</code>. It is why other containers from the Standard library also define constructor that takes <code>std::initializer_list</code> as argument. In this way, no container depends on any other container for construction from expressions of the form of <code>{value1, value2, ...., valueN}</code>. Hope that helps.

14,693,100

Pass args for script when going thru pipe

I have this example shell script: <pre><code>echo /$1/ </code></pre> So I may call <pre><code>$ . ./script 5 # output: /5/ </code></pre> I want to pipe the script into sh(ell), but can I pass the arg too ? <pre><code>cat script | sh # output: // </code></pre>

14,693,303

3

0

null

2013-02-04 18:28:46.137 UTC

9

2021-05-27 20:54:15.033 UTC

null

114,226

null

1

53

bash

19,768

You can pass arguments to the shell using the <code>-s</code> option: <pre><code>cat script | bash -s 5 </code></pre>

14,374,726

postgresql - can't create database - OperationalError: source database "template1" is being accessed by other users

I logged in to source database template1 and now I can't create database. When I try to create database, I get this error: <pre><code>OperationalError: source database "template1" is being accessed by other users DETAIL: There are 5 other session(s) using the database. </code></pre> Every time I login to template1, I use 'exit' command to logout, but as you can see it does not logout and number of sessions increases everytime I login. Is there a way to force disconnect every connection to template1 that logged in now?

14,375,832

19

3

null

2013-01-17 08:18:04.85 UTC

7

2022-08-17 22:53:32.947 UTC

null

1,455,384

null

1

59

postgresql|postgresql-8.4

67,271

This helped me solve my problem: <pre><code>SELECT *, pg_terminate_backend(procpid) FROM pg_stat_activity WHERE usename='username'; --Use pid if PostgreSQL version 9.2 or above. </code></pre> I terminated all active connections to template1 and could create database normally

14,588,727

Can not deserialize instance of java.util.ArrayList out of VALUE_STRING

I have a REST service built with Jersey and deployed in the AppEngine. The REST service implements the verb PUT that consumes an <code>application/json</code> media type. The data binding is performed by Jackson. The verb consumes an enterprise-departments relation represented in JSON as <pre><code>{"name":"myEnterprise", "departments":["HR","IT","SC"]} </code></pre> On the client side, I use gson to convert the JSON representation into a java object. Then, I pass the object to my REST service and it works fine. Problem: When my JSON representation has only one item in the collection <pre><code>{"name":"myEnterprise", "departments":["HR"]} </code></pre> the service cannot deserialize the object. <pre><code>ATTENTION: /enterprise/enterprise: org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of VALUE_STRING token at [Source: org.mortbay.jetty.HttpParser$Input@5a9c5842; line: 1, column: 2 </code></pre> As reported by other users, the solution is to add the flag <code>ACCEPT_SINGLE_VALUE_AS_ARRAY</code> (e.g., <a href="https://stackoverflow.com/questions/14319573/jersey-can-not-deserialize-instance-of-arraylist-out-of-string">Jersey: Can not deserialize instance of ArrayList out of String</a>). Nevertheless, I am not controlling an <code>ObjectMapper</code> because in the service side it is transparently made by Jackson. Question: Is there a way to configure the <code>ObjectMapper</code> on the service side to enable <code>ACCEPT_SINGLE_VALUE_AS_ARRAY</code>? annotations? <code>web.xml</code>? Code details Java object: <pre><code>@XmlRootElement public class Enterprise { private String name; private List<String> departments; public Enterprise() {} public String getName() { return name; } public void setName(String name) { this.name = name; } public List<String> getDepartments() { return departments; } public void setDepartments(List<String> departments) { this.departments = departments; } } </code></pre> The REST service side: <pre><code> @PUT @Consumes(MediaType.APPLICATION_JSON) @Produces(MediaType.APPLICATION_JSON) @Path("/enterprise") public Response putEnterprise(Enterprise enterprise, @Context HttpServletRequest req){ ... } </code></pre> Client side: <pre><code>... String jsonString = "{\"name\":\"myEnterprise\", \"departments\":[\"HR\"]}"; Enterprise enterprise = gson.fromJson(jsonString, Enterprise.class); System.out.println(gson.toJson(enterprise)); response = webResource .type(MediaType.APPLICATION_JSON) .put(ClientResponse.class,enterprise); if (response.getStatus() >= 400) { throw new RuntimeException("Failed : HTTP error code : " + response.getStatus()); } ... </code></pre>

16,071,898

5

2

null

2013-01-29 17:30:16.827 UTC

10

2020-09-20 07:55:27.303 UTC

2019-11-08 08:40:00.427 UTC

null

3,657,460

null

2,022,175

null

1

68

java|json|arraylist|jackson|json-deserialization

227,616

This is the solution for my old question: I implemented my own <code>ContextResolver</code> in order to enable the <code>DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY</code> feature. <pre><code>package org.lig.hadas.services.mapper; import javax.ws.rs.Produces; import javax.ws.rs.core.MediaType; import javax.ws.rs.ext.ContextResolver; import javax.ws.rs.ext.Provider; import org.codehaus.jackson.map.DeserializationConfig; import org.codehaus.jackson.map.ObjectMapper; @Produces(MediaType.APPLICATION_JSON) @Provider public class ObjectMapperProvider implements ContextResolver<ObjectMapper> { ObjectMapper mapper; public ObjectMapperProvider(){ mapper = new ObjectMapper(); mapper.configure(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true); } @Override public ObjectMapper getContext(Class<?> type) { return mapper; } } </code></pre> And in the <code>web.xml</code> I registered my package into the servlet definition... <pre><code><servlet> <servlet-name>...</servlet-name> <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class> <init-param> <param-name>com.sun.jersey.config.property.packages</param-name> <param-value>...;org.lig.hadas.services.mapper</param-value> </init-param> ... </servlet> </code></pre> ... all the rest is transparently done by jersey/jackson.

14,684,913

Disabling animation in ViewPager

I'd like to disable all the animations for the transitions in my custom <code>ViewPager</code>. This view pager contains four tabs -and each tab loads a <code>Fragment</code>- and what the view pager does is to switch the tabs: for example first tab is the index, second is map, etc. The problem is that if, being the first tab chosen, I click on the fourth tab, I can see how the <code>ViewPager</code> goes through the second and third tab and stops on the fourth, and I don't want that to happen. I tried to disable all the animations for this <code>ViewPager</code> trying to use a <code>setAnimation</code> to <code>null</code> every time the user chooses a new tab to be displayed, but it still doesn't work. Any idea to achieve this, please? Thanks a lot in advance! EDIT: I also tried to override <code>onCreateAnimation</code> for each <code>Fragment</code> but still not working

14,685,515

5

3

null

2013-02-04 10:36:25.337 UTC

11

2022-03-30 05:26:29.06 UTC

null

257,948

null

1

69

android|animation|android-viewpager

40,942

I finally found out: the issue can be solved by just calling the <code>mViewPager.setCurrentItem(position)</code> with an extra parameter to <code>false</code>, which is the smooth scroll for the <code>ViewPager</code>. After this, the scroll will be done without any smoothing and thus the animations won't be seen.

14,436,155

how to create inline style with :before and :after

I generated a bubble chat thingy from <a href="http://www.ilikepixels.co.uk/drop/bubbler/">http://www.ilikepixels.co.uk/drop/bubbler/</a> In my page I put a number inside of it <pre><code>.bubble { position: relative; width: 20px; height: 15px; padding: 0; background: #FFF; border: 1px solid #000; border-radius: 5px; } .bubble:after { content: ""; position: absolute; top: 4px; left: -4px; border-style: solid; border-width: 3px 4px 3px 0; border-color: transparent #FFF; display: block; width: 0; z-index: 1; } .bubble:before { content: ""; position: absolute; top: 4px; left: -5px; border-style: solid; border-width: 3px 4px 3px 0; border-color: transparent #000; display: block; width: 0; z-index: 0; } </code></pre> I want the <code>background-color</code> of the bubble to change according to the number inside of it via <code>rgb</code> so if my div is <pre><code><div class="bubble" style="background-color: rgb(100,255,255);"> 100 </div> </code></pre> I want the color to be <code>rgb(100,255,255)</code> The thing is this doesn't affect the triangle. How do I write the inline css so it will include the :before and :after?

14,436,745

5

0

null

2013-01-21 09:59:01.523 UTC

19

2021-06-08 23:08:28.203 UTC

2013-01-21 10:27:31.043 UTC

null

1,574,198

null

972,789

null

1

101

css|inline

164,313

You can't. With inline styles you are targeting the element directly. You can't use other selectors there. What you can do however is define different classes in your stylesheet that define different colours and then add the class to the element.

2,437,010

How to get objects to react to touches in Cocos2D?

Alright, so I'm starting to learn more about Coco2D, but I'm kinda frusterated. A lot of the tutorials I have found are for outdated versions of the code, so when I look through and see how they do certain things, I can't translate it into my own program, because a lot has changed. With that being said, I am working in the latest version of Coco2d, version 0.99. What I want to do is create a sprite on the screen (Done) and then when I touch that sprite, I can have "something" happen. For now, let's just make an alert go off. Now, I got this code working with the help of a friend. Here is the header file: <pre><code>// When you import this file, you import all the cocos2d classes #import "cocos2d.h" // HelloWorld Layer @interface HelloWorld : CCLayer { CGRect spRect; } // returns a Scene that contains the HelloWorld as the only child +(id) scene; @end </code></pre> And here is the implementation file: <pre><code>// // cocos2d Hello World example // http://www.cocos2d-iphone.org // // Import the interfaces #import "HelloWorldScene.h" #import "CustomCCNode.h" // HelloWorld implementation @implementation HelloWorld +(id) scene { // 'scene' is an autorelease object. CCScene *scene = [CCScene node]; // 'layer' is an autorelease object. HelloWorld *layer = [HelloWorld node]; // add layer as a child to scene [scene addChild: layer]; // return the scene return scene; } // on "init" you need to initialize your instance -(id) init { // always call "super" init // Apple recommends to re-assign "self" with the "super" return value if( (self=[super init] )) { // create and initialize a Label CCLabel* label = [CCLabel labelWithString:@"Hello World" fontName:@"Times New Roman" fontSize:64]; // ask director the the window size CGSize size = [[CCDirector sharedDirector] winSize]; // position the label on the center of the screen label.position = ccp( size.width /2 , size.height/2 ); // add the label as a child to this Layer [self addChild: label]; CCSprite *sp = [CCSprite spriteWithFile:@"test2.png"]; sp.position = ccp(300,200); [self addChild:sp]; float w = [sp contentSize].width; float h = [sp contentSize].height; CGPoint aPoint = CGPointMake([sp position].x - (w/2), [sp position].y - (h/2)); spRect = CGRectMake(aPoint.x, aPoint.y, w, h); CCSprite *sprite2 = [CCSprite spriteWithFile:@"test3.png"]; sprite2.position = ccp(100,100); [self addChild:sprite2]; //[self registerWithTouchDispatcher]; self.isTouchEnabled = YES; } return self; } // on "dealloc" you need to release all your retained objects - (void) dealloc { // in case you have something to dealloc, do it in this method // in this particular example nothing needs to be released. // cocos2d will automatically release all the children (Label) // don't forget to call "super dealloc" [super dealloc]; } - (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; //CGPoint location = [[CCDirector sharedDirector] convertCoordinate:[touch locationInView:touch.view]]; CGPoint location = [touch locationInView:[touch view]]; location = [[CCDirector sharedDirector] convertToGL:location]; if (CGRectContainsPoint(spRect, location)) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Win" message:@"testing" delegate:nil cancelButtonTitle:@"okay" otherButtonTitles:nil]; [alert show]; [alert release]; NSLog(@"TOUCHES"); } NSLog(@"Touch got"); } </code></pre> However, this only works for 1 object, the sprite which I create the CGRect for. I can't do it for 2 sprites, which I was testing. So my question is this: How can I have all sprites on the screen react to the same event when touched? For my program, the same event needs to be run for all objects of the same type, so that should make it a tad easier. I tried making a subclass of CCNode and over write the method, but that just didn't work at all... so I'm doing something wrong. Help would be appreciated! Going through the "Touches" project in cocos2D and seeing if I see how they did it. It looks like they made a subclass and overwrote the methods: <pre><code>- (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event - (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event - (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event </code></pre> So now I get to figure out why mine doesn't work... hmm...

2,437,108

2

0

null

2010-03-13 02:14:41.16 UTC

9

2014-04-06 09:46:21.29 UTC

null

3,275,134

null

200,567

null

1

8

ios|iphone|objective-c|cocoa-touch|cocos2d-iphone

19,160

I got it. I had to add some more code to the custom class: Header File: <pre><code>// // CustomCCNode.h // Coco2dTest2 // // Created by Ethan Mick on 3/11/10. // Copyright 2010 Wayfarer. All rights reserved. // #import "cocos2d.h" @interface CustomCCNode : CCSprite <CCTargetedTouchDelegate> { } @property (nonatomic, readonly) CGRect rect; @end </code></pre> Implementation: <pre><code>// // CustomCCNode.m // Coco2dTest2 // // Created by Ethan Mick on 3/11/10. // Copyright 2010 Wayfarer. All rights reserved. // #import "CustomCCNode.h" #import "cocos2d.h" @implementation CustomCCNode - (CGRect)rect { CGSize s = [self.texture contentSize]; return CGRectMake(-s.width / 2, -s.height / 2, s.width, s.height); } - (BOOL)containsTouchLocation:(UITouch *)touch { return CGRectContainsPoint(self.rect, [self convertTouchToNodeSpaceAR:touch]); } - (void)onEnter { [[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:YES]; [super onEnter]; } - (void)onExit { [[CCTouchDispatcher sharedDispatcher] removeDelegate:self]; [super onExit]; } - (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event { NSLog(@"ccTouchBegan Called"); if ( ![self containsTouchLocation:touch] ) return NO; NSLog(@"ccTouchBegan returns YES"); return YES; } - (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event { CGPoint touchPoint = [touch locationInView:[touch view]]; touchPoint = [[CCDirector sharedDirector] convertToGL:touchPoint]; NSLog(@"ccTouch Moved is called"); } - (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event { NSLog(@"ccTouchEnded is called"); } @end </code></pre>

2,438,065

How can I invoke a method with an out parameter?

I want expose WebClient.DownloadDataInternal method like below: <pre><code>[ComVisible(true)] public class MyWebClient : WebClient { private MethodInfo _DownloadDataInternal; public MyWebClient() { _DownloadDataInternal = typeof(WebClient).GetMethod("DownloadDataInternal", BindingFlags.NonPublic | BindingFlags.Instance); } public byte[] DownloadDataInternal(Uri address, out WebRequest request) { _DownloadDataInternal.Invoke(this, new object[] { address, out request }); } } </code></pre> WebClient.DownloadDataInternal has a out parameter, I don't know how to invoke it. Help!

2,438,081

2

0

null

2010-03-13 10:51:57.163 UTC

11

2017-10-29 18:12:57.23 UTC

null

107,625

null

285,996

null

1

48

c#|reflection|out-parameters

28,488

<pre><code>public class MyWebClient : WebClient { delegate byte[] DownloadDataInternal(Uri address, out WebRequest request); DownloadDataInternal downloadDataInternal; public MyWebClient() { downloadDataInternal = (DownloadDataInternal)Delegate.CreateDelegate( typeof(DownloadDataInternal), this, typeof(WebClient).GetMethod( "DownloadDataInternal", BindingFlags.NonPublic | BindingFlags.Instance)); } public byte[] DownloadDataInternal(Uri address, out WebRequest request) { return downloadDataInternal(address, out request); } } </code></pre>

2,440,729

How can I emulate a get request exactly like a web browser?

There are websites that when I open specific ajax request on browser, I get the resulted page. But when I try to load them with curl, I receive an error from the server. How can I properly emulate a get request to the server that will simulate a browser? That is what I am doing: <pre><code>$url="https://new.aol.com/productsweb/subflows/ScreenNameFlow/AjaxSNAction.do?s=username&f=firstname&l=lastname"; ini_set('user_agent', 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.0.3705; .NET CLR 1.1.4322)'); $ch = curl_init(); curl_setopt($ch, CURLOPT_URL,$url); $result=curl_exec($ch); print $result; </code></pre>

2,440,753

2

3

null

2010-03-14 00:41:37.46 UTC

14

2020-12-22 16:47:34.743 UTC

null

1,783,163

null

80,932

null

1

58

php|curl

121,857

Are you sure the curl module honors ini_set('user_agent',...)? There is an option CURLOPT_USERAGENT described at <a href="http://docs.php.net/function.curl-setopt" rel="noreferrer">http://docs.php.net/function.curl-setopt</a>. Could there also be a cookie tested by the server? That you can handle by using CURLOPT_COOKIE, CURLOPT_COOKIEFILE and/or CURLOPT_COOKIEJAR. edit: Since the request uses https there might also be error in verifying the certificate, see CURLOPT_SSL_VERIFYPEER. <pre><code>$url="https://new.aol.com/productsweb/subflows/ScreenNameFlow/AjaxSNAction.do?s=username&f=firstname&l=lastname"; $agent= 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.0.3705; .NET CLR 1.1.4322)'; $ch = curl_init(); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); curl_setopt($ch, CURLOPT_VERBOSE, true); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_USERAGENT, $agent); curl_setopt($ch, CURLOPT_URL,$url); $result=curl_exec($ch); var_dump($result); </code></pre>

1,535,443

EF Query With Conditional Include

I have two tables: a WorkItem table, and a WorkItemNote table. How do I return a WorkItem and all of the WorkItemNotes that meet a certain criteria? I think this should be simple, almost like a conditional "Include", right?

1,535,618

1

0

null

2009-10-08 03:18:47.603 UTC

18

2013-08-29 09:12:01.327 UTC

null

96,780

null

781

null

1

22

entity-framework

8,596

I've been planning on writing <a href="http://blogs.msdn.com/alexj/archive/2009/03/26/index-of-tips.aspx" rel="noreferrer">a tip</a> on this but your question beat me to the punch. Assuming a <code>WorkItem</code> has many <code>WorkItemNotes</code> you can do this: <pre><code>var intermediary = (from item in ctx.WorkItems from note in item.Notes where note.SomeProp == SomeValue select new {item, note}).AsEnumerable(); </code></pre> This produces an anonymous element for each <code>WorkItemNote</code> that matches, and holds the corresponding <code>WorkItem</code> too. EF identity resolution insures that the same <code>WorkItem</code> (by reference) is returned multiple times if it has multiple <code>WorkItemNotes</code> that match the criteria. I assume that next you want to just get back to just the <code>WorkItems</code>, like this: <pre><code>var workItems = intermediary.Select(x => x.item).Distinct().ToList(); </code></pre> Then if you now do this: <pre><code>foreach(var workItem in workItems) { Console.WriteLine(workItem.Notes.Count) } </code></pre> You will see that <code>WorkItemNotes</code> that match the original filter have been added to the Notes collection of each <code>workItem</code>. This is because of something called Relationship Fixup. I.e. this gives you what you want conditional include. Hope this helps <a href="http://twitter.com/adjames" rel="noreferrer">Alex</a>

49,807,952

How to generate UUIDs in JS or React?

In my <code>React</code> app, I want to do optimistic updates to create a responsive experience for my users. Having said that I want to send a user entry to my backend with an ID that will be used so that there won't be a different Id for the user's entry next time he/she uses the app. For example, if the user enters a comment, I want to assign its ID with a real <code>UUID</code> and then send it to my API. I understand <code>JavaScript</code> or <code>React</code> don't really have a built-in way to generate <code>UUID</code>/<code>GUID</code> values. I've seen many articles that produce randomized values that look like <code>UUID</code>/<code>GUID</code>'s but they really are not and I don't want to use them as ID's for user entries. How do I get real <code>UUID</code>/<code>GUID</code> values in my frontend? Do I call my backend API to get them? I can create an endpoint in my API that spits out 10 or 20 <code>GUID</code>'s at a time and I can store them for future use in my frontend but this sounds a bit absurd. I don't want to reinvent the wheel here as I'm not the first person to face this scenario. How do I get real <code>UUID</code> values on my frontend?

49,808,036

2

3

null

2018-04-13 01:20:27.633 UTC

4

2019-12-07 23:03:38.6 UTC

null

3,257,186

null

1,705,266

null

1

22

javascript|reactjs

85,822

You can use the <a href="https://www.npmjs.com/package/uuid" rel="noreferrer">uuid npm package</a>. You probably want to use a v4 UUID. (Previous UUID versions use things like a timestamp or network card MAC address as seeds to the random generator).

31,405,627

ui-select multiselect is very slow in displaying the choices

I ran into this problem, and I don't know how to solve it. I have used a <a href="https://github.com/angular-ui/ui-select">ui-select multiselect</a> in my page. First, a http.get request is made to a url which gets the data, then the ui-select choices are populated. The data is big - the length of the data is 2100. This data is to be shown as choices. (The data is fetched at the beginning during the loading of the page and is stored in an array) But the problem is each time I click on the multiselect to select a choice, it takes 4-5 seconds to populate the list and the page becomes very slow. What do I do to reduce this time? The choices data is stored in an array, the datatype is array of strings. <pre><code> <ui-select multiple ng-model="selectedFields.name" style="width: 100%;"> <ui-select-match placeholder="Select fields...">{{$item}}</ui-select-match> <ui-select-choices repeat="fields in availableFields | filter:$select.search"> {{fields}} </ui-select-choices> </ui-select> </code></pre> in the controller, <pre><code>$scope.selectedFields = {}; $scope.selectedFields.name = []; $scope.init = function() { $http.get(url) .success( function(response, status, headers, config) { availableFields = response; }) .error( function(err) { }); }; $scope.init(); </code></pre> If not this way, is there any other options/choice I can work with which doesn't delay showing the select-choices?

31,445,605

4

0

null

2015-07-14 11:43:37.81 UTC

9

2017-05-12 08:48:54.223 UTC

2015-07-15 05:48:23.317 UTC

null

3,449,335

null

3,449,335

null

1

20

angularjs|angular-ui|ui-select

16,189

This is a known issue in ui-select. I tried the following ways, both work 1) There is a workaround for this - use <pre><code>| limitTo: 100 </code></pre> This limits the choice display to 100 but all the choices can be selected. Look at <a href="https://github.com/angular-ui/ui-select/issues/88">this thread</a> for more details. 2) Since some of the time, there is a need to display the entire list in the choices, 1) is not a viable option. I used a different library - <a href="http://angular-js.in/selectize-js/">selectize.js</a>. Here's a <a href="http://plnkr.co/edit/X2YYPX?p=preview">plunker</a> demo given in the page

31,318,881

How do you stop Ansible from creating .retry files in the home directory?

When Ansible has problems running plays against a host, it will output the name of the host into a file in the user's home directory ending in '.retry'. These are often not used and just cause clutter, is there a way to turn them off or put them in a different directory?

31,318,882

5

0

null

2015-07-09 13:25:42.857 UTC

13

2020-12-10 15:01:53.2 UTC

null

213,269

null

144,876

null

1

159

ansible

49,783

There are two options that you can add to the [defaults] section of the ansible.cfg file that will control whether or not .retry files are created and where they are created. <pre><code>[defaults] ... retry_files_enabled = True # Create them - the default retry_files_enabled = False # Do not create them retry_files_save_path = "~/" # The directory they will go into # (home directory by default) </code></pre>

40,438,784

Read JSON file with Swift 3

I have a JSON file called points.json, and a read function like: <pre><code>private func readJson() { let file = Bundle.main.path(forResource: "points", ofType: "json") let data = try? Data(contentsOf: URL(fileURLWithPath: file!)) let jsonData = try? JSONSerialization.jsonObject(with: data!, options: []) as! [String:Any] print(jsonData) } </code></pre> It does not work, any help?

40,438,849

2

1

null

2016-11-05 13:28:09.987 UTC

9

2019-07-06 13:46:37.323 UTC

2016-11-05 13:42:47.367 UTC

null

2,227,743

null

3,235,247

null

1

40

json|swift3

46,428

Your problem here is that you force unwrap the values and in case of an error you can't know where it comes from. Instead, you should handle errors and safely unwrap your optionals. And as @vadian rightly notes in his comment, you should use <code>Bundle.main.url</code>. <pre><code>private func readJson() { do { if let file = Bundle.main.url(forResource: "points", withExtension: "json") { let data = try Data(contentsOf: file) let json = try JSONSerialization.jsonObject(with: data, options: []) if let object = json as? [String: Any] { // json is a dictionary print(object) } else if let object = json as? [Any] { // json is an array print(object) } else { print("JSON is invalid") } } else { print("no file") } } catch { print(error.localizedDescription) } } </code></pre> When coding in Swift, usually, <code>!</code> is a code smell. Of course there's exceptions (IBOutlets and others) but try to not use force unwrapping with <code>!</code> yourself and always unwrap safely instead.

27,599,965

Java better way to delete file if exists

We need to call <code>file.exists()</code> before <code>file.delete()</code> before we can delete a file E.g. <pre><code> File file = ...; if (file.exists()){ file.delete(); } </code></pre> Currently in all our project we create a static method in some util class to wrap this code. Is there some other way to achieve the same , so that we not need to copy our utils file in every other project.

27,600,014

11

0

null

2014-12-22 09:35:58.98 UTC

10

2021-05-01 07:04:12.08 UTC

2014-12-22 09:41:44.567 UTC

null

4,384,615

null

4,384,615

null

1

73

java

141,373

Starting from Java 7 you can use <a href="http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#deleteIfExists%28java.nio.file.Path%29" rel="noreferrer">deleteIfExists</a> that returns a boolean (or throw an Exception) depending on whether a file was deleted or not. This method may not be atomic with respect to other file system operations. Moreover if a file is in use by JVM/other program then on some operating system it will not be able to remove it. Every file can be converted to path via <code>toPath</code> method . E.g. <pre><code>File file = ...; boolean result = Files.deleteIfExists(file.toPath()); //surround it in try catch block </code></pre>

30,140,044

Deliver the first item immediately, 'debounce' following items

Consider the following use case: <ul> <li>need to deliver first item as soon as possible</li> <li>need to debounce following events with 1 second timeout</li> </ul> I ended up implementing custom operator based on <code>OperatorDebounceWithTime</code> then using it like this <pre><code>.lift(new CustomOperatorDebounceWithTime<>(1, TimeUnit.SECONDS, Schedulers.computation())) </code></pre> <code>CustomOperatorDebounceWithTime</code> delivers the first item immediately then uses <code>OperatorDebounceWithTime</code> operator's logic to debounce later items. Is there an easier way to achieve described behavior? Let's skip the <code>compose</code> operator, it doesn't solve the problem. I'm looking for a way to achieve this without implementing custom operators.

30,145,789

15

0

null

2015-05-09 12:40:11.173 UTC

6

2022-07-30 18:49:00.83 UTC

null

1,675,568

null

1

46

rx-java|rx-android

17,697

Update: From @lopar's comments a better way would be: <pre><code>Observable.from(items).publish(publishedItems -> publishedItems.limit(1).concatWith(publishedItems.skip(1).debounce(1, TimeUnit.SECONDS))) </code></pre> Would something like this work: <pre><code>String[] items = {"one", "two", "three", "four", "five", "six", "seven", "eight"}; Observable<String> myObservable = Observable.from(items); Observable.concat(myObservable.first(), myObservable.skip(1).debounce(1, TimeUnit.SECONDS)) .subscribe(s -> System.out.println(s)); </code></pre>

35,946,868

Adding custom jars to pyspark in jupyter notebook

I am using the Jupyter notebook with Pyspark with the following docker image: <a href="https://github.com/jupyter/docker-stacks/tree/master/all-spark-notebook" rel="noreferrer">Jupyter all-spark-notebook</a> Now I would like to write a pyspark streaming application which consumes messages from Kafka. In the <a href="http://spark.apache.org/docs/latest/streaming-kafka-integration.html" rel="noreferrer">Spark-Kafka Integration guide</a> they describe how to deploy such an application using spark-submit (it requires linking an external jar - explanation is in 3. Deploying). But since I am using Jupyter notebook I never actually run the <code>spark-submit</code> command, I assume it gets run in the back if I press execute. In the <code>spark-submit</code> command you can specify some parameters, one of them is <code>-jars</code>, but it is not clear to me how I can set this parameter from the notebook (or externally via environment variables?). I am assuming I can link this external jar dynamically via the <code>SparkConf</code> or the <code>SparkContext</code> object. Has anyone experience on how to perform the linking properly from the notebook?

36,295,208

5

0

null

2016-03-11 17:58:55.75 UTC

11

2020-02-06 03:39:19.573 UTC

2016-03-29 21:21:34.82 UTC

null

2,299,864

null

2,299,864

null

1

26

python-3.x|apache-kafka|pyspark|spark-streaming|jupyter-notebook

28,475

I've managed to get it working from within the jupyter notebook which is running form the all-spark container. I start a python3 notebook in jupyterhub and overwrite the PYSPARK_SUBMIT_ARGS flag as shown below. The Kafka consumer library was downloaded from the maven repository and put in my home directory /home/jovyan: <pre><code>import os os.environ['PYSPARK_SUBMIT_ARGS'] = '--jars /home/jovyan/spark-streaming-kafka-assembly_2.10-1.6.1.jar pyspark-shell' import pyspark from pyspark.streaming.kafka import KafkaUtils from pyspark.streaming import StreamingContext sc = pyspark.SparkContext() ssc = StreamingContext(sc,1) broker = "<my_broker_ip>" directKafkaStream = KafkaUtils.createDirectStream(ssc, ["test1"], {"metadata.broker.list": broker}) directKafkaStream.pprint() ssc.start() </code></pre> Note: Don't forget the pyspark-shell in the environment variables! Extension: If you want to include code from spark-packages you can use the --packages flag instead. An example on how to do this in the all-spark-notebook can be found <a href="https://gist.github.com/parente/c95fdaba5a9a066efaab" rel="noreferrer">here</a>

29,720,783

Projection of mongodb subdocument using C# .NET driver 2.0

I have the following structure: <pre><code>public class Category { [BsonElement("name")] public string CategoryName { get; set; } [BsonDateTimeOptions] [BsonElement("dateCreated")] public DateTime DateStamp { get; set; } [BsonElement("tasks")] public List<TaskTracker.Task> Task { get; set; } } public class Task { [BsonElement("name")] public string TaskName { get; set; } [BsonElement("body")] public string TaskBody { get; set; } } </code></pre> I am trying to query a <code>Category</code> to get all the <code>TaskName</code> values and then return them to a list to be displayed in a list box. I have tried using this query: <pre><code>var getTasks = Categories.Find<Category>(x => x.CategoryName == catName) .Project(Builders<Category>.Projection .Include("tasks.name") .Exclude("_id")) .ToListAsync() .Result; </code></pre> But what get returned is: <code>{"tasks": [{"name: "test"}]}</code>. Is there anyway to just return the string value?

29,722,097

2

0

null

2015-04-18 17:52:37.287 UTC

3

2019-01-23 09:49:08.233 UTC

2015-04-18 18:17:30.047 UTC

null

918,624

null

4,578,699

null

1

15

c#|.net|mongodb|mongodb-.net-driver

38,996

As Avish said, you have to use the aggregation API to get the resulting document to look like you are wanting. However, the driver can make some of that disappear for you if you use the expression tree API for project as you have done for Find. For instance, I believe the following should work for you: <pre><code>var taskNames = await Categores.Find(x => x.CategoryName == catName) .Project(x => x.Tasks.Select(y => y.Name)) .ToListAsync(); </code></pre> This should just bring back an enumerable of strings (<code>tasks.name</code>) for each category. The driver will be inspecting this projection and only pull back the <code>tasks.name</code> field.

36,607,979

How to get around property does not exist on 'Object'

I'm new to Typescript, and not sure how to word this question. I need to access two "possible" properties on an object that is passed in the constructor. I know im missing some checks to see if they are defined, but Typescript is throwing me a "Property does not exist on 'Object'" message. The message appears on the selector and template returns. <pre><code>class View { public options:Object = {}; constructor(options:Object) { this.options = options; } selector ():string { return this.options.selector; } template ():string { return this.options.template; } render ():void { } } </code></pre> I'm sure its fairly simple, but Typescript is new to me.

36,608,015

2

0

null

2016-04-13 19:36:29.59 UTC

8

2020-03-21 20:06:21.65 UTC

2017-07-13 22:18:08.96 UTC

null

4,409,409

null

5,812,315

null

1

72

object|typescript

99,072

If you use the <code>any</code> type instead of <code>Object</code>, you can access any property without compile errors. However, I would advise to create an interface that marks the possible properties for that object: <pre><code>interface Options { selector?: string template?: string } </code></pre> Since all of the fields use <code>?:</code>, it means that they might or might not be there. So this works: <pre><code>function doStuff(o: Options) { //... } doStuff({}) // empty object doStuff({ selector: "foo" }) // just one of the possible properties doStuff({ selector: "foo", template: "bar" }) // all props </code></pre> If something comes from javascript, you can do something like this: <pre><code>import isObject from 'lodash/isObject' const myOptions: Options = isObject(somethingFromJS) // if an object ? (somethingFromJS as Options) // cast it : {} // else create an empty object doStuff(myOptions) // this works now </code></pre> Of course this solution only works as expected if you are only unsure about the presence of a property not of it's type.

3,130,911

tcpdump: localhost to localhost

I write a program that send TCP packets from localhost to localhost. And I want to use tcpdump to capture the packets. But nothing is captured. My command in Ubuntu: <pre><code>sudo tcpdump </code></pre> What argument shall I add? Thanks!

3,130,925

1

null

2010-06-28 08:15:42.027 UTC

24

2021-12-17 23:56:08.023 UTC

null

343,606

null

1

118

linux|localhost|tcpdump

92,518

<pre><code>sudo tcpdump -i lo </code></pre> <h3>Notes</h3> <ul> <li>If you get <code>tcpdump: lo: No such device exists</code>, get the name by coping it from the output of</li> </ul> <pre><code>sudo tcpdump -D </code></pre> For example, if the output is as below you need <code>lo0</code> (which is reusult <code>9.</code> here: <pre><code>1.en0 [Up, Running] 2.p2p0 [Up, Running] 3.awdl0 [Up, Running] 4.llw0 [Up, Running] 5.utun0 [Up, Running] 6.utun1 [Up, Running] 7.utun2 [Up, Running] 8.utun3 [Up, Running] 9.lo0 [Up, Running, Loopback] </code></pre>

38,556,579

Is it possible to type-hint a compiled regex in python?

I would like to use autocompletion for a pre-compiled and stored list of regular expressions, but it doesn't appear that I can import the _sre.SRE_Pattern class, and I can't programmatically feed the obtained type from type() to a comment of the format # type: classname or use it for a return -> classname style hint Is there a way to explicitly import a class from the _sre.c thing?

38,935,153

1

2

null

2016-07-24 20:41:47.95 UTC

1

2021-04-08 21:16:28.01 UTC

null

1,698,431

null

551,577

null

1

45

python|regex|type-hinting

10,693

You should use <a href="https://docs.python.org/3/library/typing.html#typing.Pattern" rel="noreferrer"><code>typing.Pattern</code> and <code>typing.Match</code></a> which were specifically added to the typing module to accommodate this use case. Example: <pre><code>from typing import Pattern, Match import re my_pattern = re.compile("[abc]*") # type: Pattern[str] my_match = re.match(my_pattern, "abbcab") # type: Match[str] print(my_match) </code></pre>

58,791,938

C# 8 understanding await using syntax

I have next method: <pre><code>public async Task<IEnumerable<Quote>> GetQuotesAsync() { using var connection = new SqlConnection(_connectionString); var allQuotes = await connection.QueryAsync<Quote>(@"SELECT [Symbol], [Bid], [Ask], [Digits] FROM [QuoteEngine].[RealtimeData]"); return allQuotes; } </code></pre> Everything fine and clear, connection will be disposed at the end of scope. But resharper suggests to change it to: <pre><code>public async Task<IEnumerable<Quote>> GetQuotesAsync() { await using var connection = new SqlConnection(_connectionString); var allQuotes = await connection.QueryAsync<Quote>(@"SELECT [Symbol], [Bid], [Ask], [Digits] FROM [QuoteEngine].[RealtimeData]"); return allQuotes; } </code></pre> It adds await before using and code is compiled successfully. What does it mean and when do we need to do that?

58,792,016

2

0

null

2019-11-10 18:56:01.473 UTC

9

2021-12-05 17:15:52.163 UTC

2020-04-09 16:07:52.063 UTC

null

4,728,685

null

1,017,161

null

1

104

c#|async-await|resharper|using|c#-8.0

41,542

Similar as <code>using (...)</code> uses <code>IDisposable</code> to clean up resources, <code>await using (...)</code> uses <a href="https://docs.microsoft.com/en-us/dotnet/api/system.iasyncdisposable?view=dotnet-plat-ext-3.0" rel="noreferrer">IAsyncDisposable</a>. This allows to perform also time-consuming tasks (e.g involving I/O) on cleanup without blocking.

5,960,731

Strange behavior of select/dropdown's onchange() JS event when using 'Next' on Mobile Safari Dropdown list item select box

This is a hard one to articulate and I am new to mobile web development so please bear with me: On my webpage, I have 3 Nested dropdown lists (Area, Town, Street). Nested as in, each dropdown's items are modified when the selection in the dropdown above it changes. e.g selecting an Area changes the Town and Street lists and selecting a Town changes the Street list. I use XMLHTTPRequests in the onchange() javascript event of the dropdowns to fetch and populate the other downdowns. This works fine on Android and Desktop browsers. On Mobile Safari, when a drowdown is touched, a list is shown where the user can select items. In addition the selection box has the "Previous/Next/Autofill/Done" buttons to navigate to other form elements. So the user touches the first dropdown, selects a value and presses the Next button. This causes two problems: First, On this action the first dropdown's oncange() event is not triggered reliably! Sometimes it fires sometimes not. If after selecting an Area, the user touches somewhere else on the webpage or presses the "Done" button then the onchange() is fired normally and the Towns and Streets are populated normally. Second, the element that comes into focus when pressing then "Next" button is the dropdown whos elements need to be changed after being fetched. When the onchange() of the previous dropdown does get fired then, either the list is no updated or the items in the select box turn blue and all of them have a tick mark showing that they are all selected.. From what i can tell the problem would be solved if i can disable the Next/Previous buttons in the selection box or somehow fix how the onchange() is fired and the next in focus dropdown's list items are repopulated while it is in focus. Here is the code (simplified): <pre><code><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta name="viewport" content="width=device-width; initial-scale=1.0; maximum-scale=1.0; user-scalable=no" /> <title></title> </head> <body onload="AppStart();"> <form action="#"> Area: <select id="ddlArea"> <option value="">-- Select Area -- </option> <option value="1">Area 1</option> <option value="2">Area 2</option> <option value="3">Area 3</option> <option value="4">Area 4</option> <option value="5">Area 5</option> </select> Town: <select id="ddlTown"> <option value="">Please wait ...</option> </select> Street: <select id="ddlStreet"> <option value="">-- Select Area or Town -- </option> </select> Unit: <select id="ddlUnit"> <option value="">-- No Street Selected -- </option> </select> <script type="text/javascript"> var ddlArea, ddlTown, ddlStreet, ddlUnit; function AppStart() { ddlArea = document.getElementById("ddlArea"); ddlTown = document.getElementById("ddlTown"); ddlStreet = document.getElementById("ddlStreet"); ddlUnit = document.getElementById("ddlUnit"); ddlArea.onchange = areaChanged; ddlTown.onchange = townChanged; ddlStreet.onchange = streetChanged; setTimeout(function() { updateTown(""); }, 250); } var areaId = "", townId = "", streetId = "", unitId = ""; function areaChanged(e) { areaId = ddlArea.options[ddlArea.selectedIndex].value ddlClear(ddlTown, createOption("Please Wait...", "")); ddlClear(ddlStreet, createOption("Please Wait...", "")); ddlClear(ddlUnit, createOption("-- No Street Selected --", "")); setTimeout(function() { updateTown(areaId); }, 500); setTimeout(function() { updateStreet(areaId, ""); }, 700); } function townChanged(e) { townId = ddlTown.options[ddlTown.selectedIndex].value ddlClear(ddlStreet, createOption("Please Wait...", "")); ddlClear(ddlUnit, createOption("-- No Street Selected --", "")); setTimeout(function() { updateStreet(areaId, townId); }, 400); } function streetChanged(e) { streetId = ddlStreet.options[ddlStreet.selectedIndex].value ddlClear(ddlUnit, createOption("Please Wait...", "")); setTimeout(function() { updateUnit(streetId); }, 600); } function updateTown(areaID) { ddlClear(ddlTown, createOption("-- Select Town --", "")); var items = isNaN(parseInt(areaID)) ? 10 : parseInt(areaID); if (areaID == "") areaID = "ALL"; for (var i = 0; i < items; i++) { ddlTown.appendChild(createOption("Town " + (i+1) + ", Area " + areaID, i)); } } function updateStreet(areaID, townID) { ddlClear(ddlStreet, createOption("-- Select Street --", "")); var items1 = isNaN(parseInt(areaID)) ? 10 : parseInt(areaID); var items2 = isNaN(parseInt(townID)) ? 10 : parseInt(townID); var items = items1 + items2; if (areaID == "") areaID = "ALL"; if (townID = "") townId = "ALL"; for (var i = 0; i < items; i++) { ddlStreet.appendChild(createOption("Street " + (i + 1) + ", Area " + areaID + ", Town " + townID, i)); } } function updateUnit(streetID) { ddlClear(ddlUnit, createOption("-- Select Unit --", "")); var items = isNaN(parseInt(streetID)) ? 10 : parseInt(streetID); if (streetID == "") streetID = "ALL"; for (var i = 0; i < items; i++) { ddlUnit.appendChild(createOption("Unit " + (i + 1) + ", Street " + streetID, i)); } } function ddlClear(Dropdown, option) { while (Dropdown.options.length > 0) { try { Dropdown.options[0] = null; } catch (e) { }; } if (option != null) { Dropdown.appendChild(option); } } function createOption(text, value) { var oOption = document.createElement("OPTION"); oOption.innerHTML = text; oOption.value = value; return oOption; } </script> </form> </body> </html> </code></pre> Help. :/

7,284,325

1

0

null

2011-05-11 07:31:09.86 UTC

10

2011-10-14 19:31:58.233 UTC

2011-05-11 10:40:50.037 UTC

null

187,025

null

187,025

null

1

14

javascript|iphone|web-applications|mobile-safari|mobile-website

26,885

I had the same problem on my site. I was able to fix it by manually polling the <code>selectedIndex</code> property on the select control. That way it fires as soon as you "check" the item in the list. Here's a jQuery plugin I wrote to do this: <pre><code>$.fn.quickChange = function(handler) { return this.each(function() { var self = this; self.qcindex = self.selectedIndex; var interval; function handleChange() { if (self.selectedIndex != self.qcindex) { self.qcindex = self.selectedIndex; handler.apply(self); } } $(self).focus(function() { interval = setInterval(handleChange, 100); }).blur(function() { window.clearInterval(interval); }) .change(handleChange); //also wire the change event in case the interval technique isn't supported (chrome on android) }); }; </code></pre> You use it just like you would use the "change" event. For instance: <pre><code>$("#mySelect1").quickChange(function() { var currVal = $(this).val(); //populate mySelect2 }); </code></pre> Edit: Android does not focus the select when you tap it to select a new value, but it also does not have the same problem that iphone does. So fix it by also wiring the old <code>change</code> event.

54,398,579

Example for transactions in mongodb with GoLang

I need an example to implement transactions in MongoDB with GoLang. I'm using this golang driver for mongodb <a href="https://github.com/mongodb/mongo-go-driver" rel="noreferrer">https://github.com/mongodb/mongo-go-driver</a> There is no clear documentation for how to implement transactions. Can anyone help me?

54,401,731

2

0

null

2019-01-28 09:08:23.85 UTC

12

2021-05-27 13:24:31.523 UTC

null

2,481,981

null

1

10

mongodb|go|transactions

12,656

It can be confusing. Below is a simple example. <pre><code>if session, err = client.StartSession(); err != nil { t.Fatal(err) } if err = session.StartTransaction(); err != nil { t.Fatal(err) } if err = mongo.WithSession(ctx, session, func(sc mongo.SessionContext) error { if result, err = collection.UpdateOne(sc, bson.M{"_id": id}, update); err != nil { t.Fatal(err) } if result.MatchedCount != 1 || result.ModifiedCount != 1 { t.Fatal("replace failed, expected 1 but got", result.MatchedCount) } if err = session.CommitTransaction(sc); err != nil { t.Fatal(err) } return nil }); err != nil { t.Fatal(err) } session.EndSession(ctx) </code></pre> You can view full <a href="https://github.com/simagix/mongo-go-examples/blob/master/examples/transaction_test.go" rel="noreferrer">examples here</a>.

25,247,218

Servlet Filter: How to get all the headers from servletRequest?

Here is how my <code>WebFilter</code> looks like <pre><code>@WebFilter("/rest/*") public class AuthTokenValidatorFilter implements Filter { @Override public void init(final FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse, final FilterChain filterChain) throws IOException, ServletException { final Enumeration<String> attributeNames = servletRequest.getAttributeNames(); while (attributeNames.hasMoreElements()) { System.out.println("{attribute} " + servletRequest.getParameter(attributeNames.nextElement())); } final Enumeration<String> parameterNames = servletRequest.getParameterNames(); while (parameterNames.hasMoreElements()) { System.out.println("{parameter} " + servletRequest.getParameter(parameterNames.nextElement())); } filterChain.doFilter(servletRequest, servletResponse); } @Override public void destroy() { } } </code></pre> I tried to find out online as to how to get values for <code>HTTP headers</code> coming from request. I did not find anything, so I tried to enumerate on <code>servletRequest.getAttributeNames()</code> and <code>servletRequest.getParameterNames()</code> without knowing anything, but I do not get any headers. Question How can I get all the headers coming from the request?

25,247,239

4

0

null

2014-08-11 15:44:18.557 UTC

15

2022-07-24 01:08:50.823 UTC

null

379,235

null

1

84

java|jakarta-ee|servlets|servlet-filters

142,446

Typecast <code>ServletRequest</code> into <code>HttpServletRequest</code> (only if <code>ServletRequest request</code> is an <code>instanceof</code> <code>HttpServletRequest</code>). Then you can use <code>HttpServletRequest.getHeader()</code> and <code>HttpServletRequest.getHeaderNames()</code> method. Something like this: <pre><code>@Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpRequest = (HttpServletRequest) request; Enumeration<String> headerNames = httpRequest.getHeaderNames(); if (headerNames != null) { while (headerNames.hasMoreElements()) { System.out.println("Header: " + httpRequest.getHeader(headerNames.nextElement())); } } //doFilter chain.doFilter(httpRequest, response); } </code></pre>

51,947,791

Javadoc "cannot find symbol" error when using Lombok's @Builder annotation

I have a class looking as below : <pre><code>@Data @Builder public class Foo { private String param; /** My custom builder.*/ public static FooBuilder builder(String _param){ return builder().param(_param); } } </code></pre> I get the following error : <blockquote> [ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.10.4:javadoc (default-cli) on project foo: An error has occurred in JavaDocs report generation: [ERROR] Exit code: 1 - /home/workspace/foo/src/main/java/com/foo/Foo.java:34: error: cannot find symbol [ERROR] public static FooBuilder builder(String _param) [ERROR] ^ [ERROR] symbol: class FooBuilder [ERROR] location: class Foo </blockquote>

51,947,792

3

0

null

2018-08-21 11:32:39.447 UTC

7

2022-03-19 18:39:45.883 UTC

2019-10-17 08:18:32.433 UTC

null

1,746,118

null

3,817,953

null

1

30

java|maven|javadoc|lombok|maven-javadoc-plugin

12,299

In order to solve this issue, I have to use Lombok's <code>delombok</code> feature (cf : <a href="https://projectlombok.org/features/delombok" rel="noreferrer">https://projectlombok.org/features/delombok</a>). <blockquote> lombok doesn't cover all tools. For example, lombok cannot plug into javadoc ... which run on java sources. Delombok still allows you to use lombok with these tools by preprocessing your java code into java code with all of lombok's transformations already applied. </blockquote> I did this using Maven by adding the following plugins : <pre><code><plugin> <groupId>org.projectlombok</groupId> <artifactId>lombok-maven-plugin</artifactId> <version>1.18.0.0</version> <configuration> <sourceDirectory>${project.basedir}/src/main/java</sourceDirectory> <outputDirectory>${delombok.output}</outputDirectory> <addOutputDirectory>false</addOutputDirectory> </configuration> <executions> <execution> <phase>generate-sources</phase> <goals> <goal>delombok</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-javadoc-plugin</artifactId> <version>2.9</version> <configuration> <sourcepath>${delombok.output}</sourcepath> </configuration> </plugin> </code></pre>

2,450,373

Set global hotkeys using C#

I need to capture a key press when my program is not in focus. (ie. <kbd>Ctrl</kbd>+<kbd>Alt</kbd>+<kbd>J</kbd>) and trigger an event in my program. Thus far i have found this dll that appears to be the correct path" <pre><code>[DllImport("user32.dll")]private static extern int RegisterHotKey(IntPtr hwnd, int id,int fsModifiers, int vk); [DllImport("user32.dll")] private static extern int UnregisterHotKey(IntPtr hwnd, int id); </code></pre>

27,309,185

3

4

2010-06-19 00:39:31.11 UTC

2010-03-15 20:47:39.22 UTC

52

2020-12-22 16:53:22.62 UTC

2017-01-01 09:43:00.56 UTC

null

1,033,581

null

72,136

null

1

87

c#|.net|hotkeys

97,653

Please note that this code will not trigger events in console application projects. You have to use WinForms project for events to fire. This is the correct code: <pre><code>public sealed class KeyboardHook : IDisposable { // Registers a hot key with Windows. [DllImport("user32.dll")] private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk); // Unregisters the hot key with Windows. [DllImport("user32.dll")] private static extern bool UnregisterHotKey(IntPtr hWnd, int id); /// <summary> /// Represents the window that is used internally to get the messages. /// </summary> private class Window : NativeWindow, IDisposable { private static int WM_HOTKEY = 0x0312; public Window() { // create the handle for the window. this.CreateHandle(new CreateParams()); } /// <summary> /// Overridden to get the notifications. /// </summary> /// <param name="m"></param> protected override void WndProc(ref Message m) { base.WndProc(ref m); // check if we got a hot key pressed. if (m.Msg == WM_HOTKEY) { // get the keys. Keys key = (Keys)(((int)m.LParam >> 16) & 0xFFFF); ModifierKeys modifier = (ModifierKeys)((int)m.LParam & 0xFFFF); // invoke the event to notify the parent. if (KeyPressed != null) KeyPressed(this, new KeyPressedEventArgs(modifier, key)); } } public event EventHandler<KeyPressedEventArgs> KeyPressed; #region IDisposable Members public void Dispose() { this.DestroyHandle(); } #endregion } private Window _window = new Window(); private int _currentId; public KeyboardHook() { // register the event of the inner native window. _window.KeyPressed += delegate(object sender, KeyPressedEventArgs args) { if (KeyPressed != null) KeyPressed(this, args); }; } /// <summary> /// Registers a hot key in the system. /// </summary> /// <param name="modifier">The modifiers that are associated with the hot key.</param> /// <param name="key">The key itself that is associated with the hot key.</param> public void RegisterHotKey(ModifierKeys modifier, Keys key) { // increment the counter. _currentId = _currentId + 1; // register the hot key. if (!RegisterHotKey(_window.Handle, _currentId, (uint)modifier, (uint)key)) throw new InvalidOperationException("Couldn’t register the hot key."); } /// <summary> /// A hot key has been pressed. /// </summary> public event EventHandler<KeyPressedEventArgs> KeyPressed; #region IDisposable Members public void Dispose() { // unregister all the registered hot keys. for (int i = _currentId; i > 0; i--) { UnregisterHotKey(_window.Handle, i); } // dispose the inner native window. _window.Dispose(); } #endregion } /// <summary> /// Event Args for the event that is fired after the hot key has been pressed. /// </summary> public class KeyPressedEventArgs : EventArgs { private ModifierKeys _modifier; private Keys _key; internal KeyPressedEventArgs(ModifierKeys modifier, Keys key) { _modifier = modifier; _key = key; } public ModifierKeys Modifier { get { return _modifier; } } public Keys Key { get { return _key; } } } /// <summary> /// The enumeration of possible modifiers. /// </summary> [Flags] public enum ModifierKeys : uint { Alt = 1, Control = 2, Shift = 4, Win = 8 } </code></pre> to use (i had to edit the modifier keys to cast them (modifier)1 (modifier)2 etc <pre><code>public partial class Form1 : Form { KeyboardHook hook = new KeyboardHook(); public Form1() { InitializeComponent(); // register the event that is fired after the key press. hook.KeyPressed += new EventHandler<KeyPressedEventArgs>(hook_KeyPressed); // register the control + alt + F12 combination as hot key. hook.RegisterHotKey(ModifierKeys.Control | ModifierKeys.Alt, Keys.F12); } void hook_KeyPressed(object sender, KeyPressedEventArgs e) { // show the keys pressed in a label. label1.Text = e.Modifier.ToString() + " + " + e.Key.ToString(); } } </code></pre>

36,378,751

Services depending on each other

In my Angular 2 app, I have two services that depend on each other (service A calling methods from service B and vice versa). Here are the relevant code: <code>app.component.ts</code>: <pre><code>import {Component} from 'angular2/core'; import {TempService} from '../services/tmp'; import {Temp2Service} from '../services/tmp2'; @Component({ selector: 'my-app', templateUrl: 'app/app/app.component.html', providers: [TempService, Temp2Service] }) export class AppComponent { (...) } </code></pre> Service 1: <pre><code>import {Injectable} from 'angular2/core'; import {Temp2Service} from './tmp2'; @Injectable() export class TempService { constructor (private _sessionService: Temp2Service) {} } </code></pre> Service 2: <pre><code>import {Injectable} from 'angular2/core'; import {TempService} from './tmp'; @Injectable() export class Temp2Service { constructor (private _sessionService: TempService) {} } </code></pre> Running the app leads to the following error: <blockquote> EXCEPTION: Cannot resolve all parameters for 'Temp2Service'(undefined). Make sure that all the parameters are decorated with Inject or have valid type annotations and that 'Temp2Service' is decorated with Injectable </blockquote> When commenting the constructor in one of the services, the app runs fine. So my guess is that the "cross-reference" of the two services is causing the problem. Do you have an idea what is going wrong here? Or is my approach already wrong?

36,378,859

12

1

null

2016-04-02 21:12:39.003 UTC

11

2021-11-23 22:04:02.003 UTC

2019-06-28 21:34:31.883 UTC

null

3,345,644

null

1,313,884

null

1

82

angular

76,290

This is a called circular dependency. It is not an issue with Angular2 itself. It is not allowed in any language I am aware of. You will need to refactor your code to remove this circular dependency. Likely you will need to breakup one of these services into new service. If you follow the single responsibility principle you will find you won't get into circular dependency trap.

52,631,057

How to delete existing text from input using Puppeteer?

I'm trying to test amending text in an editable input which contains the title of the current record - and I want to able to test editing such text, replacing it with something else. I know I can use <code>await page.type('#inputID', 'blah');</code> to insert "blah" into the textbox (which in my case, having existing text, only appends "blah"), however, I cannot find any page methods<a href="https://pptr.dev/#?product=Puppeteer&version=v1.8.0&show=api-class-page" rel="noreferrer">1</a> that allow deleting or replacing existing text.

52,633,235

9

1

null

2018-10-03 15:49:57.303 UTC

13

2022-09-20 05:03:08.727 UTC

2018-10-03 18:52:22.287 UTC

null

4,283,581

null

8,215,719

null

1

55

javascript|node.js|google-chrome-devtools|puppeteer|headless-browser

57,402

You can use <code>page.evaluate</code> to manipulate DOM as you see fit: <pre><code>await page.evaluate( () => document.getElementById("inputID").value = "") </code></pre> However sometimes just manipulating a given field might not be enough (a target page could be an SPA with event listeners), so emulating real keypresses is preferable. The examples below are from <a href="https://github.com/GoogleChrome/puppeteer/issues/761" rel="nofollow noreferrer">the informative issue</a> in puppeteer's Github concerning this task. Here we press <code>Backspace</code> as many times as there are characters in that field: <pre><code>const inputValue = await page.$eval('#inputID', el => el.value); // focus on the input field await page.click('#inputID'); for (let i = 0; i < inputValue.length; i++) { await page.keyboard.press('Backspace'); } </code></pre> Another interesting solution is to click the target field 3 times so that the browser would select all the text in it and then you could just type what you want: <pre><code>const input = await page.$('#inputID'); await input.click({ clickCount: 3 }) await input.type("Blah"); </code></pre>

51,415,784

How to add my own function as a custom stage in a ML pyspark Pipeline?

The sample code from Florian <pre><code>-----------+-----------+-----------+ |ball_column|keep_the |hall_column| +-----------+-----------+-----------+ | 0| 7| 14| | 1| 8| 15| | 2| 9| 16| | 3| 10| 17| | 4| 11| 18| | 5| 12| 19| | 6| 13| 20| +-----------+-----------+-----------+ </code></pre> The first part of the code drops columns name in the banned list <pre><code>#first part of the code banned_list = ["ball","fall","hall"] condition = lambda col: any(word in col for word in banned_list) new_df = df.drop(*filter(condition, df.columns)) </code></pre> So the above piece of code should drop the <code>ball_column</code> and <code>hall_column</code>. The second part of the code buckets specific columns in the list. For this example, we will bucket the only one remaining, <code>keep_column</code>. <pre><code>bagging = Bucketizer( splits=[-float("inf"), 10, 100, float("inf")], inputCol='keep_the', outputCol='keep_the') </code></pre> Now bagging the columns using pipeline was as follows <pre><code>model = Pipeline(stages=bagging).fit(df) bucketedData = model.transform(df) </code></pre> How can I add the first block of the code (<code>banned list</code>, <code>condition</code>, <code>new_df</code>) to the ml pipeline as a stage?

51,417,421

1

0

null

2018-07-19 06:30:44.877 UTC

10

2018-08-29 21:00:16.743 UTC

2018-07-21 07:50:13.99 UTC

null

10,020,360

null

10,020,360

null

1

11

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

8,419

I believe this does what you want. You can create a custom <code>Transformer</code>, and add that to the stages in the <code>Pipeline</code>. Note that I slightly changed your functions because we do not have access to all variables you mentioned, but the concept remains the same. Hope this helps! <pre><code>import pyspark.sql.functions as F from pyspark.ml import Pipeline, Transformer from pyspark.ml.feature import Bucketizer from pyspark.sql import DataFrame from typing import Iterable import pandas as pd # CUSTOM TRANSFORMER ---------------------------------------------------------------- class ColumnDropper(Transformer): """ A custom Transformer which drops all columns that have at least one of the words from the banned_list in the name. """ def __init__(self, banned_list: Iterable[str]): super(ColumnDropper, self).__init__() self.banned_list = banned_list def _transform(self, df: DataFrame) -> DataFrame: df = df.drop(*[x for x in df.columns if any(y in x for y in self.banned_list)]) return df # SAMPLE DATA ----------------------------------------------------------------------- df = pd.DataFrame({'ball_column': [0,1,2,3,4,5,6], 'keep_the': [6,5,4,3,2,1,0], 'hall_column': [2,2,2,2,2,2,2] }) df = spark.createDataFrame(df) # EXAMPLE 1: USE THE TRANSFORMER WITHOUT PIPELINE ----------------------------------- column_dropper = ColumnDropper(banned_list = ["ball","fall","hall"]) df_example = column_dropper.transform(df) # EXAMPLE 2: USE THE TRANSFORMER WITH PIPELINE -------------------------------------- column_dropper = ColumnDropper(banned_list = ["ball","fall","hall"]) bagging = Bucketizer( splits=[-float("inf"), 3, float("inf")], inputCol= 'keep_the', outputCol="keep_the_bucket") model = Pipeline(stages=[column_dropper,bagging]).fit(df) bucketedData = model.transform(df) bucketedData.show() </code></pre> Output: <pre><code>+--------+---------------+ |keep_the|keep_the_bucket| +--------+---------------+ | 6| 1.0| | 5| 1.0| | 4| 1.0| | 3| 1.0| | 2| 0.0| | 1| 0.0| | 0| 0.0| +--------+---------------+ </code></pre> <hr> Also, note that if your custom method requires to be fitted (e.g. a custom <code>StringIndexer</code>), you should also create a custom <code>Estimator</code>: <pre><code>class CustomTransformer(Transformer): def _transform(self, df) -> DataFrame: class CustomEstimator(Estimator): def _fit(self, df) -> CustomTransformer: </code></pre>

38,168,391

Cross-platform file name handling in .NET Core

How to handle file name in <code>System.IO</code> classes in a cross-platform manner to make it work on Windows and Linux? For example, I write this code that works perfectly on Windows, however it doesn't create a file on Ubuntu Linux: <pre><code>var tempFilename = $@"..\Data\uploads\{filename}"; using (FileStream fs = System.IO.File.Create(tempFilename)) { file.CopyTo(fs); fs.Flush(); } </code></pre>

38,168,532

9

0

null

2016-07-03 09:03:32.693 UTC

5

2022-08-12 07:20:24.683 UTC

2017-03-01 17:01:35.417 UTC

null

240,733

null

2,000,124

null

1

52

c#|linux|.net-core

51,096

Windows using Backslash. Linux using Slash. Path.Combine set the right symbol : <a href="https://msdn.microsoft.com/en-us/library/fyy7a5kt(v=vs.110).aspx" rel="noreferrer">Path.Combine Method - MSDN</a>

629,617

How to convert string to "iso-8859-1"?

How can i convert an UTF-8 string into an ISO-8859-1 string?

629,629

2

1

null

2009-03-10 10:36:04.31 UTC

1

2009-03-10 10:39:49.307 UTC

2009-03-10 10:38:28.157 UTC

Ólafur Waage

22,459

Tom

20,979

null

1

13

c#|asp.net

41,009

Try: <pre><code> System.Text.Encoding iso_8859_1 = System.Text.Encoding.GetEncoding("iso-8859-1"); System.Text.Encoding utf_8 = System.Text.Encoding.UTF8; // Unicode string. string s_unicode = "abcéabc"; // Convert to ISO-8859-1 bytes. byte[] isoBytes = iso_8859_1.GetBytes(s_unicode); // Convert to UTF-8. byte[] utf8Bytes = System.Text.Encoding.Convert(iso_8859_1, utf_8, isoBytes); </code></pre>

1,134,770

How to end / Force a close to a program (in Clojure)

I am a pretty decent programmer in Java, however I am new to programming in Clojure. In Java, to force an exit of a program, the code used is <code>System.exit(0)</code>. Is there any equivalent to this code is Clojure?

1,134,778

2

0

null

2009-07-16 00:10:39.047 UTC

4

2016-05-23 16:38:33.743 UTC

2016-05-23 16:37:21.36 UTC

null

206,720

Hank

null

1

34

clojure|exit

13,814

Given that part of the attractiveness of Clojure is that you can use Java class libraries, why not just do: <pre><code>(System/exit 0) </code></pre>

1,119,849

How do I use Optional Parameters in an ASP.NET MVC Controller

I have a set of drop down controls on a view that are linked to two lists. <pre><code>//control ViewData["Countries"] = new SelectList(x.getCountries().ToList(), "key","value",country); ViewData["Regions"] = new SelectList(x.getRegions(country).ToList(), "id", "name", regions); /* on the view */ <% using (Html.BeginForm("","", FormMethod.Get)) { %> <ol> <li> <%= MvcEasyA.Helpers.LabelHelper.Label("Country", "Country:")%> <%= Html.DropDownList("Country", ViewData["Countries"] as SelectList) %> <input type="submit" value="countryGO" class="ddabtns" /> </li> <li> <%= MvcEasyA.Helpers.LabelHelper.Label("Regions", "Regions:")%> <%= Html.DropDownList("Regions", ViewData["Regions"] as SelectList,"-- Select One --") %> <input type="submit" value="regionsGO" class="ddabtns" /> </li> </ol> <input type="submit" value="go" /> <% } %> </code></pre> So its sending a query to the same page (as its only really there to provide an alternative way of setting/updating the appropriate dropdowns, this is acceptable as it will all be replaced with javascript). The url on clicking is something like... <pre><code>http://localhost:1689/?country=FRA&regions=117 </code></pre> Regions is dependent on the country code. I'm trying to achieve this bit without bothering with routing as there's no real point with regards this function. So the Controller has the following method. <pre><code>public ActionResult Index(string country, int regions) </code></pre>

1,119,951

2

0

null

2009-07-13 14:40:02.56 UTC

4

2018-09-19 05:24:22.443 UTC

2016-03-17 15:20:07.47 UTC

null

3,688,464

null

52,912

null

1

45

c#|asp.net-mvc|c#-3.0

106,935

The string should be ok, as it'll get passed as an empty string. For int, make it nullable: <pre><code>public ActionResult Index(string Country, int? Regions) </code></pre> Also, you'll note I capitalized it in the same was as your querystring. Edit Note that ASP.NET now allows you to define default parameters. E.g.: <pre><code>public ActionResult Index(string Country, int Regions = 2) </code></pre> However, IMHO I'd recommend that you only use the default where it makes semantic sense. For example, if the purpose of the Regions parameter were to set the # of regions in a country, and most countries have 2 regions (North and South) then setting a default makes sense. I wouldn't use a "magic number" that signifies a lack of input (e.g., 999 or -1) -- at that point you should just use <code>null</code>.

2,799,017

Is it possible to bind a List to a ListView in WinForms?

I'd like to bind a ListView to a <code>List<string></code>. I'm using this code: <pre><code>somelistview.DataBindings.Add ("Items", someclass, "SomeList"); </code></pre> I'm getting this exception: Cannot bind to property 'Items' because it is read-only. I don't know how I should bind if the Items property is readonly?

2,799,161

5

0

null

2010-05-09 20:12:55.393 UTC

2

2022-03-01 20:57:17.963 UTC

null

39,590

null

1

19

c#|winforms|data-binding

65,979

The ListView class does not support design time binding. An alternative is presented in <a href="http://www.codeproject.com/KB/list/ListView_DataBinding.aspx" rel="noreferrer">this project</a>.

2,912,054

Lazy Load images on Listview in android(Beginner Level)?

<blockquote> Possible Duplicate: <a href="https://stackoverflow.com/questions/541966/android-how-do-i-do-a-lazy-load-of-images-in-listview">Android - How do I do a lazy load of images in ListView</a> </blockquote> I am working on the listview with the custom adapter. I want to load the images and text view on it. The images are load from the internet urls. I just want to show the images which are visible list item to hte user. I refered the <a href="http://code.google.com/p/shelves/source/browse/trunk/Shelves/src/org/curiouscreature/android/shelves/activity/BooksAdapter.java" rel="noreferrer">Shelves opensource project example from romainguy</a>, but its to complicated to understand the code. For a beginner level, I just want to know how to handle the tag between the adapter and activity. From the <a href="http://www.androidguys.com/2008/07/22/fancy-listviews-part-three/" rel="noreferrer">commonsware</a> <a href="http://github.com/commonsguy/cwac-thumbnail/tree" rel="noreferrer">example</a> I can set the tag on adapter, but can't show the corresponding image at the idle state of the listview. Please help me with your ideas. Sample codes are more understandable. Thanks. EDIT: The combination of <a href="http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/List14.html" rel="noreferrer">Efficient</a> and <a href="http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/List13.html" rel="noreferrer">Slow</a> Adapter in ApiDemos is more helpful to understand. changes done on efficient adapter example like this: <pre><code>public class List14 extends ListActivity implements ListView.OnScrollListener { // private TextView mStatus; private static boolean mBusy = false; static ViewHolder holder; public static class EfficientAdapter extends BaseAdapter { private LayoutInflater mInflater; private Bitmap mIcon1; private Bitmap mIcon2; public EfficientAdapter(Context context) { // Cache the LayoutInflate to avoid asking for a new one each time. mInflater = LayoutInflater.from(context); // Icons bound to the rows. mIcon1 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_1); mIcon2 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_2); } /** * The number of items in the list is determined by the number of * speeches in our array. * * @see android.widget.ListAdapter#getCount() */ public int getCount() { return DATA.length; } /** * Since the data comes from an array, just returning the index is * sufficent to get at the data. If we were using a more complex data * structure, we would return whatever object represents one row in the * list. * * @see android.widget.ListAdapter#getItem(int) */ public Object getItem(int position) { return position; } /** * Use the array index as a unique id. * * @see android.widget.ListAdapter#getItemId(int) */ public long getItemId(int position) { return position; } /** * Make a view to hold each row. * * @see android.widget.ListAdapter#getView(int, android.view.View, * android.view.ViewGroup) */ public View getView(int position, View convertView, ViewGroup parent) { // A ViewHolder keeps references to children views to avoid // unneccessary calls // to findViewById() on each row. // When convertView is not null, we can reuse it directly, there is // no need // to reinflate it. We only inflate a new View when the convertView // supplied // by ListView is null. if (convertView == null) { convertView = mInflater.inflate(R.layout.list_item_icon_text, null); // Creates a ViewHolder and store references to the two children // views // we want to bind data to. holder = new ViewHolder(); holder.text = (TextView) convertView.findViewById(R.id.text); holder.icon = (ImageView) convertView.findViewById(R.id.icon); convertView.setTag(holder); } else { // Get the ViewHolder back to get fast access to the TextView // and the ImageView. holder = (ViewHolder) convertView.getTag(); } if (!mBusy) { holder.icon.setImageBitmap(mIcon1); // Null tag means the view has the correct data holder.icon.setTag(null); } else { holder.icon.setImageBitmap(mIcon2); // Non-null tag means the view still needs to load it's data holder.icon.setTag(this); } holder.text.setText(DATA[position]); // Bind the data efficiently with the holder. // holder.text.setText(DATA[position]); return convertView; } static class ViewHolder { TextView text; ImageView icon; } } private Bitmap mIcon1; private Bitmap mIcon2; @Override public void onCreate(Bundle savedInstanceState) { mIcon1 = BitmapFactory.decodeResource(this.getResources(), R.drawable.icon48x48_1); mIcon2 = BitmapFactory.decodeResource(this.getResources(), R.drawable.icon48x48_2); super.onCreate(savedInstanceState); setListAdapter(new EfficientAdapter(this)); getListView().setOnScrollListener(this); } public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { } public void onScrollStateChanged(AbsListView view, int scrollState) { switch (scrollState) { case OnScrollListener.SCROLL_STATE_IDLE: mBusy = false; int first = view.getFirstVisiblePosition(); int count = view.getChildCount(); for (int i = 0; i < count; i++) { holder.icon = (ImageView) view.getChildAt(i).findViewById( R.id.icon); if (holder.icon.getTag() != null) { holder.icon.setImageBitmap(mIcon1); holder.icon.setTag(null); } } // mStatus.setText("Idle"); break; case OnScrollListener.SCROLL_STATE_TOUCH_SCROLL: mBusy = true; // mStatus.setText("Touch scroll"); break; case OnScrollListener.SCROLL_STATE_FLING: mBusy = true; // mStatus.setText("Fling"); break; } } private static final String[] DATA = { "Abbaye de Belloc", "Abbaye du Mont des Cats", "Abertam", "Abondance", "Ackawi", "Acorn", "Adelost", "Affidelice au Chablis", "Afuega'l Pitu"}; } </code></pre> It works fine now. But when the scrolling state its not reloading the image properly. some interval of items not shows the images2. that is the correct order of the images are loading. But not in all items of list. Mismatches happening between solid item intervals. how to correct it?

2,923,196

5

0

null

2010-05-26 10:26:09.707 UTC

28

2012-07-18 00:14:37.417 UTC

2017-05-23 12:10:09.08 UTC

null

-1

null

267,269

null

1

54

android|listview|android-lazyadapter|android-lazyloading

47,100

Praveen - As you already found my blog post on this, I just wanted to push it back to Stackoverflow so that others can use it. Here's the basic discussion: <a href="http://ballardhack.wordpress.com/2010/04/05/loading-remote-images-in-a-listview-on-android/" rel="noreferrer">http://ballardhack.wordpress.com/2010/04/05/loading-remote-images-in-a-listview-on-android/</a> And there's a class I documented later that uses a thread and a callback to load the images: <a href="http://ballardhack.wordpress.com/2010/04/10/loading-images-over-http-on-a-separate-thread-on-android/" rel="noreferrer">http://ballardhack.wordpress.com/2010/04/10/loading-images-over-http-on-a-separate-thread-on-android/</a> Update: To address your specific exception, I think that view returned in the list from <code>getChildAt</code> is not an <code>ImageView</code> -- it's whatever layout view you are using to hold the image and text. Update to include relevant code: (Per @george-stocker's recommendation) Here is the adapter I was using: <pre><code>public class MediaItemAdapter extends ArrayAdapter<MediaItem> { private final static String TAG = "MediaItemAdapter"; private int resourceId = 0; private LayoutInflater inflater; private Context context; private ImageThreadLoader imageLoader = new ImageThreadLoader(); public MediaItemAdapter(Context context, int resourceId, List<MediaItem> mediaItems) { super(context, 0, mediaItems); this.resourceId = resourceId; inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); this.context = context; } @Override public View getView(int position, View convertView, ViewGroup parent) { View view; TextView textTitle; TextView textTimer; final ImageView image; view = inflater.inflate(resourceId, parent, false); try { textTitle = (TextView)view.findViewById(R.id.text); image = (ImageView)view.findViewById(R.id.icon); } catch( ClassCastException e ) { Log.e(TAG, "Your layout must provide an image and a text view with ID's icon and text.", e); throw e; } MediaItem item = getItem(position); Bitmap cachedImage = null; try { cachedImage = imageLoader.loadImage(item.thumbnail, new ImageLoadedListener() { public void imageLoaded(Bitmap imageBitmap) { image.setImageBitmap(imageBitmap); notifyDataSetChanged(); } }); } catch (MalformedURLException e) { Log.e(TAG, "Bad remote image URL: " + item.thumbnail, e); } textTitle.setText(item.name); if( cachedImage != null ) { image.setImageBitmap(cachedImage); } return view; } } </code></pre>

2,429,819

Why is the W3C box model considered better?

Why do most developers consider the W3C <a href="https://en.wikipedia.org/wiki/CSS_box_model" rel="nofollow noreferrer">box model</a> to be better than the box model used by Internet Explorer? It's very frustrating developing pages that look the way you want them on Internet Explorer, but I find the W3C box model counterintuitive. For example, if margins, padding, and border were factored into the width, I could assign width values to all my columns without worrying about the number of columns, and any changes I make to their padding and margins. With W3C's box model I have to worry about the number of columns I have, and develop something akin to a mathematical formula to calculate the correct width values when modifying margins and padding. Changing their values would be difficult, especially for complex layouts. Consider this small frame-work I wrote: <pre><code>#content { margin:0 auto 30px auto; padding:0 30px 30px 30px; width: 900px; } #content .column { float: left; margin:0 20px 20px 20px; } #content .first { margin-left: 0; } #content .last { margin-right: 0; } .width_1-4 { width: 195px; } .width_1-3 { width: 273px; } .width_1-2 { width: 430px; } .width_3-4 { width: 645px; } .width_1-1 { width: 900px; } </code></pre> The values I assigned here will falter unless there are three columns, and thus margins at <code>0+20+20+20+20+0</code>. It would be difficult to modify padding and margins; my entire widths would have to be recalculated. If column width incorporated padding and margins, all I would need to do is change the width and I have my layout. I'm less criticizing the box model and more hoping to understand why it's considered better as I'm finding it difficult to work with. Am I doing this thing wrong? It just seems counterintuitive to use W3C's box model.

2,429,849

6

3

null

2010-03-12 01:02:36.05 UTC

14

2020-05-09 14:23:42.29 UTC

null

63,550

null

276,959

null

1

38

layout|css

11,852

One word answer - <code>-box-sizing</code> <a href="http://www.quirksmode.org/css/box.html" rel="noreferrer">You choose how you want your box model to work</a>.

3,211,991

Does IE 8 have a limit on number of stylesheets per page?

In <a href="https://stackoverflow.com/questions/3211885/is-there-any-limit-on-css-file-size/3211946#3211946">an answer about CSS</a>, a user said: <blockquote> Internet Explorer <strike>has</strike> is said to have a limit of 4096 CSS rules per file. <a href="http://msdn.microsoft.com/en-us/library/aa358796(VS.85).aspx" rel="nofollow noreferrer">Reference</a> Also, it has a limit on the number of style sheets you can embed in a single document. I think it is 20. </blockquote> While the <a href="http://msdn.microsoft.com/en-us/library/aa358796(VS.85).aspx" rel="nofollow noreferrer">reference on MSDN</a> seems to confirm this (and there's <a href="http://joshua.perina.com/africa/gambia/fajara/post/internet-explorer-css-file-size-limit" rel="nofollow noreferrer">a blog post</a> which confirms this in IE7), is this still the case for IE8?

3,212,065

6

13

null

2010-07-09 11:05:03.98 UTC

9

2015-03-27 09:46:06.327 UTC

2017-05-23 11:45:38.073 UTC

null

-1

null

19,746

null

1

40

css|internet-explorer|internet-explorer-8

15,615

Yes, IE8 (and even IE9 apparently) limit the number of style sheets to 31 per page. Telerik has <a href="http://blogs.telerik.com/aspnetmvcteam/posts/10-05-03/internet-explorer-css-limits.aspx" rel="noreferrer">an article</a> and <a href="http://demos.telerik.com/testcases/BrokenTheme.aspx" rel="noreferrer">test page</a> which demonstrate the issue. According to comments in the same article, the 4096 rules per file limitation has been marked as Won't Fix in Microsoft Connect but I've been unable to verify that.

2,651,632

How to check if an Object is a Collection Type in Java?

By using java reflection, we can easily know if an object is an array. What's the easiest way to tell if an object is a collection(Set,List,Map,Vector...)?

2,651,644

6

0

null

2010-04-16 08:40:06.16 UTC

19

2015-12-30 12:46:04.02 UTC

null

241,824

null

1

84

java

122,375

<pre><code>if (x instanceof Collection<?>){ } if (x instanceof Map<?,?>){ } </code></pre>

2,389,846

Python Decimals format

WHat is a good way to format a python decimal like this way? 1.00 --> '1' 1.20 --> '1.2' 1.23 --> '1.23' 1.234 --> '1.23' 1.2345 --> '1.23'

2,390,047

6

1

null

2010-03-05 20:51:59.863 UTC

19

2022-09-02 15:57:07.277 UTC

2010-03-05 21:15:31.543 UTC

null

190,597

null

124,503

null

1

89

python|decimal

218,149

If you have Python 2.6 or newer, use <a href="http://docs.python.org/library/string.html#format-string-syntax" rel="noreferrer"><code>format</code></a>: <pre><code>'{0:.3g}'.format(num) </code></pre> For Python 2.5 or older: <pre><code>'%.3g'%(num) </code></pre> Explanation: <code>{0}</code>tells <code>format</code> to print the first argument -- in this case, <code>num</code>. Everything after the colon (:) specifies the <code>format_spec</code>. <code>.3</code> sets the precision to 3. <code>g</code> removes insignificant zeros. See <a href="http://en.wikipedia.org/wiki/Printf#fprintf" rel="noreferrer">http://en.wikipedia.org/wiki/Printf#fprintf</a> For example: <pre><code>tests=[(1.00, '1'), (1.2, '1.2'), (1.23, '1.23'), (1.234, '1.23'), (1.2345, '1.23')] for num, answer in tests: result = '{0:.3g}'.format(num) if result != answer: print('Error: {0} --> {1} != {2}'.format(num, result, answer)) exit() else: print('{0} --> {1}'.format(num,result)) </code></pre> yields <pre><code>1.0 --> 1 1.2 --> 1.2 1.23 --> 1.23 1.234 --> 1.23 1.2345 --> 1.23 </code></pre> <hr> Using Python 3.6 or newer, you could use <a href="https://www.python.org/dev/peps/pep-0498/#code-equivalence" rel="noreferrer"><code>f-strings</code></a>: <pre><code>In [40]: num = 1.234; f'{num:.3g}' Out[40]: '1.23' </code></pre>

2,989,829

How to create a menu tree using HTML

I need to create a menu tree using HTML. I had a search on Google, but they are providing some software to download in order to create this. But I need some script and HTML tags to do this. Can anyone help me solve this problem. Thanks in advance.

2,989,890

7

3

null

2010-06-07 13:18:05.68 UTC

1

2014-02-20 19:30:29.343 UTC

2010-06-07 13:23:13.987 UTC

null

339,850

null

360,453

null

1

10

javascript|jquery|html

48,184

Here is something very simple to start with. <a href="http://www.dynamicdrive.com/dynamicindex1/navigate1.htm" rel="noreferrer">http://www.dynamicdrive.com/dynamicindex1/navigate1.htm</a> <h2>EDIT</h2> Implementing what I learned from @sushil bharwani. Here is how I found the above URL i.e. at the courtesy of @sushil bharwani <a href="http://www.google.co.in/search?q=Menu+Tree+using+UL+L&qscrl=1" rel="noreferrer">http://www.google.co.in/search?q=Menu+Tree+using+UL+L&qscrl=1</a>

2,672,975

Django BigInteger auto-increment field as primary key?

I'm currently building a project which involves a lot of collective intelligence. Every user visiting the web site gets created a unique profile and their data is later used to calculate best matches for themselves and other users. By default, Django creates an INT(11) <code>id</code> field to handle models primary keys. I'm concerned with this being overflown very quickly (i.e. ~2.4b devices visiting the page without prior cookie set up). How can I change it to be represented as BIGINT in MySQL and long() inside Django itself? I've found I could do the following (<a href="http://docs.djangoproject.com/en/dev/ref/models/fields/#bigintegerfield" rel="noreferrer">http://docs.djangoproject.com/en/dev/ref/models/fields/#bigintegerfield</a>): <pre><code>class MyProfile(models.Model): id = BigIntegerField(primary_key=True) </code></pre> But is there a way to make it autoincrement, like usual <code>id</code> fields? Additionally, can I make it unsigned so that I get more space to fill in? Thanks!

70,112,662

7

0

null

2010-04-20 06:19:55.99 UTC

19

2021-11-25 14:19:00.947 UTC

null

275,725

null

1

35

python|django|primary-key|auto-increment|biginteger

28,821

Since Django 3.2 the type of implicit primary key can be controlled with the <code>DEFAULT_AUTO_FIELD</code> setting (<a href="https://docs.djangoproject.com/en/3.2/ref/settings/#default-auto-field" rel="nofollow noreferrer">documentation</a>). So, there is no need anymore to override primary keys in all your models. <pre><code>#This setting will change all implicitly added primary keys to BigAutoField DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField' </code></pre> Note that starting with Django 3.2 new projects are generated with <code>DEFAULT_AUTO_FIELD</code> set to <code>BigAutoField</code> (<a href="https://docs.djangoproject.com/en/3.2/releases/3.2/#customizing-type-of-auto-created-primary-keys" rel="nofollow noreferrer">release notes</a>).

2,346,011

How do I scroll to an element within an overflowed Div?

I have 20 list items inside of a div that can only show 5 at a time. What is a good way to scroll to item #10, and then item #20? I know the height of all the items. The <code>scrollTo</code> plugin does this, but its source is not super easy to understand without really getting into it. I don't want to use this plugin. Let's say I have a function that takes 2 elements <code>$parentDiv</code>, <code>$innerListItem</code>, neither <code>$innerListItem.offset().top</code> nor <code>$innerListItem.positon().top</code> gives me the correct scrollTop for $parentDiv.

5,267,018

7

null

2010-02-27 02:28:22.19 UTC

47

2020-08-20 12:20:43.933 UTC

2016-04-14 16:47:30.54 UTC

null

1,694,962

null

26,188

null

1

170

jquery

151,931

The <code>$innerListItem.position().top</code> is actually relative to the <code>.scrollTop()</code> of its first positioned ancestor. So the way to calculate the correct <code>$parentDiv.scrollTop()</code> value is to begin by making sure that <code>$parentDiv</code> is positioned. If it doesn't already have an explicit <code>position</code>, use <code>position: relative</code>. The elements <code>$innerListItem</code> and all its ancestors up to <code>$parentDiv</code> need to have no explicit position. Now you can scroll to the <code>$innerListItem</code> with: <pre><code>// Scroll to the top $parentDiv.scrollTop($parentDiv.scrollTop() + $innerListItem.position().top); // Scroll to the center $parentDiv.scrollTop($parentDiv.scrollTop() + $innerListItem.position().top - $parentDiv.height()/2 + $innerListItem.height()/2); </code></pre>

10,758,471

pass php array to jquery function

I got a page with a form to fill it with custormers info. I got previous custormers data stored in a php array. With a dropdownlist users can fill the form with my stored data. what i have is a jquery function that triggers when the value changes and inside that function i whould like to update the form values with my stored data (in my php array). Problem is that i dont know how to pass my php array to the jquery function, any idea ?? this is how i fill the array: <pre><code>$contador_acompanantes = 0; foreach ($acompanantes->Persona as $acomp) { $numero = $acomp->Numero; $apellidos = $acomp->Apellidos; $nombre = $acomp->Nombre; $ACOMPANANTES[$contador_acompanantes] = $ficha_acomp; $contador_acompanantes++; } </code></pre> got my select object: <pre><code><select name="acompanante_anterior" id="acompanante_anterior"> <option value="1" selected>Acompañante</option> <option value="2">acompanante1</option> <option value="2">acompanante2</option> </select> </code></pre> and this is my code for the jquery function (it is in the same .php page) <pre><code><script type="text/javascript"> $(document).ready(function() { $('#acompanante_anterior').on('change', function() { }); }); </script> </code></pre>

10,758,535

3

0

null

2012-05-25 16:55:35.22 UTC

3

2012-05-25 17:17:37.96 UTC

null

1,361,401

null

1

6

php|jquery|arrays

38,042

<pre><code>var arrayFromPHP = <?php echo json_encode($phpArray); ?>; $.each(arrayFromPHP, function (i, elem) { // do your stuff }); </code></pre>

10,556,556

Insert all data of a datagridview to database at once

I have a datagridview which is created by various action and user's manipulation of data. I want to insert all the data of the gridview to the database at once, I know I could try a code similar to this: <pre><code>for(int i=0; i< dataGridView1.Rows.Count;i++) { string StrQuery= @"INSERT INTO tableName VALUES (" + dataGridView1.Rows[i].Cells["ColumnName"].Value +", " + dataGridView1.Rows[i].Cells["ColumnName"].Value +");"; try { using (SqlConnection conn = new SqlConnection(ConnString)) { using (SqlCommand comm = new SqlCommand(StrQuery, conn)) { conn.Open(); comm.ExecuteNonQuery(); } } } </code></pre> But will it be fair to create a new connection every time a record is inserted? The datagrid may contain many rows... Is there any way to take off all the data to the server at once and loop inside in sql to insert all the data?

10,556,681

8

0

null

2012-05-11 18:16:34.903 UTC

8

2021-11-03 09:06:46.293 UTC

2014-04-11 20:30:01.543 UTC

null

258,113

null

1,330,837

null

1

9

c#|sql-server|winforms

133,472

If you move your for loop, you won't have to make multiple connections. Just a quick edit to your code block (by no means completely correct): <pre><code>string StrQuery; try { using (SqlConnection conn = new SqlConnection(ConnString)) { using (SqlCommand comm = new SqlCommand()) { comm.Connection = conn; conn.Open(); for(int i=0; i< dataGridView1.Rows.Count;i++) { StrQuery= @"INSERT INTO tableName VALUES (" + dataGridView1.Rows[i].Cells["ColumnName"].Text+", " + dataGridView1.Rows[i].Cells["ColumnName"].Text+");"; comm.CommandText = StrQuery; comm.ExecuteNonQuery(); } } } } </code></pre> As to executing multiple SQL commands at once, please look at this link: <a href="https://stackoverflow.com/questions/3149469/multiple-statements-in-single-sqlcommand">Multiple statements in single SqlCommand</a>

10,436,231

Tooltips with Twitter Bootstrap

I am using Twitter Bootstrap--and I am not a frontend developer! However, it's making the process almost--dare I say--fun! I'm a bit confused about tooltips. They are <a href="http://getbootstrap.com/javascript/#tooltips">covered in the documentation</a> but Twitter assumes some knowledge. For example, they say to trigger the tooltip with the following JavaScript code. <pre><code>$('#example').tooltip(options) </code></pre> After poking around on their source, I realized that fields with tooltips need to be in a class and have the following code run. <pre><code>$('.tooltipclass').tooltip(options) </code></pre> But now my question is, why doesn't Twitter Bootstrap provide such a class <code>tooltip</code>? Just to allow greater configuration? Is it better to add the individual elements with tooltips to <code>tooltipclass</code>, or should I add the surrounding area to <code>tooltipclass</code>? Does it matter if I use a class identifier (<code>.class</code>) instead of a name identifier (<code>#name</code>)?

10,437,711

7

0

null

2012-05-03 17:13:50.683 UTC

27

2015-09-29 20:07:19.413 UTC

2013-12-19 11:31:15.677 UTC

null

397,598

null

568,393

null

1

71

javascript|twitter-bootstrap

103,684

I think your question boils down to what proper selector to use when setting up your tooltips, and the answer to that is almost whatever you want. If you want to use a class to trigger your tooltips you can do that, take the following for example: <pre><code><a href="#" class="link" data-original-title="first tooltip">Hover me for a tooltip</a> </code></pre> Then you can trigger all links with the <code>.link</code> class attached as tooltips like so: <pre><code>$('.link').tooltip() </code></pre> Now, to answer your question as to why the bootstrap developers did not use a class to trigger tooltips that is because it is not needed exactly, you can pretty much use any selectors you want to target your tooltips, such as (my personal favorite) the <code>rel</code> attribute. With this attribute you can target all links or elements with the <code>rel</code> property set to <code>tooltip</code>, like so: <pre><code>$('[rel=tooltip]').tooltip() </code></pre> And your links would look like something like this: <pre><code><a href="#" rel="tooltip" data-original-title="first tooltip">Hover me for a tooltip</a> </code></pre> Of course, you can also use a container class or id to target your tooltips inside an specific container that you want to single out with an specific option or to separate from the rest of your content and you can use it like so: <pre><code>$('#example').tooltip({ selector: "a[rel=tooltip]" }) </code></pre> This selector will target all of your tooltips with the <code>rel</code> attribute "within" your <code>#example</code> div, this way you can add special styles or options to that section alone. In short, you can pretty much use any valid selector to target your tooltips and there is no need to dirty your markup with an extra class to target them.

5,728,885

How do I draw an image based on a simple polygon?

I'd like to copy a roughly rectangular area to a rectangular area. Example: <img src="https://i.stack.imgur.com/S99Hf.png" alt=""> Both areas are defined by their corner points. The general direction is kept (no flipping etc). Simply rotating the source image does not work since opposing sides may be of different length. So far I found no way to do this in pure C# (except manual pixel copying), so I guess I have to resort to the Windows API or some 3rd party library?

5,730,761

2

0

null

2011-04-20 10:31:34.81 UTC

10

2013-07-17 03:45:36.33 UTC

null

39,590

null

1

13

c#|.net|image-manipulation

6,229

Generally speaking, what you want to do is map the destination coordinates to the source coordinates through a transform function: <pre><code>for (int y = 0; y < destHeight; y++) { for (x=0; x < destWidth; x++) { Color c = Transform(x, y, sourceImage, sourceTransform); SetPixel(destImage, x, y, c); } } </code></pre> Let's assume that sourceTransform is an object that encapsulates a transformation from source to dest coordinates (and vice versa). Working in dest coordinates will make it easier to avoid that curve in your retransformed source image and will allow you to better antialias, as you can map the corners of the dest pixel to the source image and sample within it and interpolate/extrapolate. In your case you're going to have a set of linear equations that do the mapping - in this case this is known as quadrilateral warping - <a href="https://stackoverflow.com/questions/2992264/extracting-a-quadrilateral-image-to-a-rectangle">see this previous question</a>.

33,326,699

Passing (laravel) Array in Javascript

I want to pass/store Laravel array in JavaScript variable. I used <code>->all()</code> so I get the result like this rather than object: <pre><code>array:83 [▼ 0 => 1 1 => 11 2 => 12 ... ] </code></pre> I can access this in view using <code>{{ $theArray }}</code>. However whatever I tried, I couldn't make this to javascript array. I tried <code>var array = {{ $theArray }};</code> <code>var array = {{{ $theArray }}};</code> I feel like I'm close but I couldn't figure it out

48,648,482

10

0

null

2015-10-25 05:58:19.427 UTC

12

2022-05-25 02:24:43.57 UTC

2015-10-25 06:03:23.597 UTC

null

3,037,257

null

4,705,339

null

1

42

javascript|php|jquery|arrays|laravel

57,266

<pre><code>var app = @json($array); </code></pre> Works like a charm

30,901,174

How to show/hide hidden HTML table rows using JavaScript (no jQuery)

Edit: This has been answered below. I would like to have an HTML table that has hidden rows between each row with more information about the top level rows. When clicking an expand/collapse image link in the first column, the hidden row's visibility will toggle from display:none; to display:table-row;. I have not written JavaScript in a while and need to be able to do this strictly in JavaScript and cannot use the jQuery toggle() method. How can I use JavaScript to find the sibling with class="subRow" of the with class="parentRow" that the button is located in within the table and then toggle the visibility of that sibling row? <h2>HTML</h2> <pre><code><table style="width:50%"> <caption>Test Table</caption> <thead> <tr align="center"> <th>State Icon</th> <th>Column 2</th> <th>Column 3</th> <th>Column 4</th> <th>Column 5</th> </tr> </thead> <tbody> <tr align="center" class="parentRow"> <td><a href="#" onclick="toggleRow();"><img alt="Expand row" height="20px;" src="expand.png"></a></td> <td>test cell</td> <td>test cell</td> <td>test cell</td> <td>test cell</td> </tr> <tr style="display: none;" class="subRow"> <td colspan="5">Lorem ipsum dolor sit amet...</td> </tr> .... </tbody> </table> </code></pre> <h2>CSS</h2> <pre><code>.offscreen { position: absolute; left: -1000px; top: 0px; overflow:hidden; width:0; } .subRow { background-color: #CFCFCF; } </code></pre> <h2>JavaScript</h2> <pre><code>function toggleRow() { var rows = document.getElementsByClassName("parentRow").nextSibling; rows.style.display = rows.style.display == "none" ? "table-row" : "none"; } </code></pre>

30,901,515

3

0

null

2015-06-17 19:55:17.067 UTC

1

2015-06-17 20:22:21.333 UTC

null

1,609,347

null

1,609,347

null

1

4

javascript|html|css|toggle|html-table

50,066

Pass your event handler a reference to the row that is clicked using <code>this</code>: <pre><code><td><a href="#" onclick="toggleRow(this);"><img alt="Expand row" height="20px;" src="expand.png"></a></td> </code></pre> Then update your toggleRow function as follows: <pre><code>function toggleRow(e){ var subRow = e.parentNode.parentNode.nextElementSibling; subRow.style.display = subRow.style.display === 'none' ? 'table-row' : 'none'; } </code></pre> You may want to consider creating a general-purpose function to navigate up the DOM tree (so that this function won't break when/if you change your HTML).

34,350,406

How rails database connection pool works

I am learning rails database connection pool concept. In rails application I have defined pool size of 5. my understanding about connection pool size is as below. <ol> <li>When server start rails automatically creates n number of connection defined in the database.yml file. In my case it will create 5 connection since pool size is 5.</li> <li>On every http request if there is need to access database then rails will use available connection from the connection pool to serve the request.</li> </ol> But my question is if I hit 1000 request at a time then most of the request will not get access to database connection because my connection pool size is only 5. Is my above understanding about rails connection pool is right?? Thanks,

34,351,364

2

0

null

2015-12-18 07:25:05.867 UTC

5

2020-07-28 10:21:30.63 UTC

2018-11-26 09:21:35.217 UTC

null

3,090,068

null

2,274,074

null

1

29

mysql|ruby-on-rails|ruby|ruby-on-rails-3|connection-pooling

21,471

Purpose: Database connections are not thread safe; so ActiveRecord uses separate database connection for each thread. Limiting factor: Total database connections is limited by the database server you use (e.g Posgres: <a href="https://www.postgresql.org/docs/current/runtime-config-connection.html" rel="noreferrer">default is typically 100 or lesser</a>), by your app server's configuration (number of processes/threads available) and Active Record's configuration : <a href="https://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/ConnectionPool.html" rel="noreferrer">Connection Pool</a> defaults to 5 . Pool size: Active Record's pool size is for a single process. A thread uses a connection from this pool and releases it automatically afterwards. (unless you spawn a thread yourself, then you'll have to manually release it). If your application is running on multiple processes, you will have 5 database connections for each of them. If your server is hit by 1000 requests concurrently, it will distribute the requests among these connections, when it gets full, rest of the requests wait for their turn. Read more at: <a href="https://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/ConnectionPool.html" rel="noreferrer">https://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/ConnectionPool.html</a>

17,731,477

Python mock class instance variable

I'm using Python's <code>mock</code> library. I know how to mock a class instance method by following the <a href="http://www.voidspace.org.uk/python/mock/getting-started.html#mocking-classes" rel="noreferrer">document</a>: <pre><code>>>> def some_function(): ... instance = module.Foo() ... return instance.method() ... >>> with patch('module.Foo') as mock: ... instance = mock.return_value ... instance.method.return_value = 'the result' ... result = some_function() ... assert result == 'the result' </code></pre> However, tried to mock a class instance variable but doesn't work (<code>instance.labels</code> in the following example): <pre><code>>>> with patch('module.Foo') as mock: ... instance = mock.return_value ... instance.method.return_value = 'the result' ... instance.labels = [1, 1, 2, 2] ... result = some_function() ... assert result == 'the result' </code></pre> Basically I want <code>instance.labels</code> under <code>some_function</code> get the value I want. Any hints?

17,731,909

1

0

null

2013-07-18 18:42:47.507 UTC

9

2013-07-18 21:52:20.373 UTC

null

477,865

null

1

21

python|unit-testing|mocking

70,804

This version of <code>some_function()</code> prints mocked <code>labels</code> property: <pre><code>def some_function(): instance = module.Foo() print instance.labels return instance.method() </code></pre> My <code>module.py</code>: <pre><code>class Foo(object): labels = [5, 6, 7] def method(self): return 'some' </code></pre> Patching is the same as yours: <pre><code>with patch('module.Foo') as mock: instance = mock.return_value instance.method.return_value = 'the result' instance.labels = [1,2,3,4,5] result = some_function() assert result == 'the result </code></pre> Full console session: <pre><code>>>> from mock import patch >>> import module >>> >>> def some_function(): ... instance = module.Foo() ... print instance.labels ... return instance.method() ... >>> some_function() [5, 6, 7] 'some' >>> >>> with patch('module.Foo') as mock: ... instance = mock.return_value ... instance.method.return_value = 'the result' ... instance.labels = [1,2,3,4,5] ... result = some_function() ... assert result == 'the result' ... ... [1, 2, 3, 4, 5] >>> </code></pre> For me your code is working.

35,565,278

SSL Localhost Privacy error

I setup ssl on localhost (wamp), I made the ssl crt with GnuWIn32. When I try to login with fb in Chrome I get the following message: URL: <pre><code>https://localhost/ServerSide/fb-callback.php?code=.....#_=_ </code></pre> Error: <blockquote> Your connection is not private. Attackers might be trying to steal your information from localhost (for example, passwords, messages, or credit cards). NET::ERR_CERT_INVALID. localhost normally uses encryption to protect your information. When Chrome tried to connect to localhost this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be localhost, or a Wi-Fi sign-in screen has interrupted the connection. Your information is still secure because Chrome stopped the connection before any data was exchanged. You cannot visit localhost right now because the website sent scrambled credentials that Chrome cannot process. Network errors and attacks are usually temporary, so this page will probably work later. </blockquote> My SSL Config: <pre><code>Listen 443 SSLCipherSuite HIGH:MEDIUM:!aNULL:!MD5 SSLPassPhraseDialog builtin SSLSessionCache "shmcb:c:/wamp/www/ssl/logs/ssl_scache(512000)" SSLSessionCacheTimeout 300 <VirtualHost *:443> DocumentRoot "c:/wamp/www" ServerName localhost:443 ServerAdmin [email protected] ErrorLog "c:/wamp/logs/error.log" TransferLog "c:/wamp/logs/access.log" SSLEngine on SSLCertificateFile "c:/wamp/www/ssl/ia.crt" SSLCertificateKeyFile "c:/wamp/www/ssl/ia.key" <FilesMatch "\.(cgi|shtml|phtml|php)$"> SSLOptions +StdEnvVars </FilesMatch> <Directory "c:/Apache24/cgi-bin"> SSLOptions +StdEnvVars </Directory> BrowserMatch "MSIE [2-5]" nokeepalive ssl-unclean-shutdown \ downgrade-1.0 force-response-1.0 CustomLog "c:/wamp/logs/ssl_request.log" \ "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b" </VirtualHost> </code></pre> My question is how to setup valid SSL certificate on localhost? or do I need to edit my configuration?

41,020,281

3

0

null

2016-02-22 22:33:22.477 UTC

16

2022-09-13 16:46:33.417 UTC

2016-12-07 14:42:12.477 UTC

null

2,788,896

null

5,052,909

null

1

56

google-chrome|ssl|localhost|wamp|self-signed

51,127

In Chrome (including version <code>Version 105</code>), browse url: <blockquote> <code>chrome://flags/#allow-insecure-localhost</code> </blockquote> and select <code>Enabled</code> to allow insecure localhost. <a href="https://i.stack.imgur.com/DNYWM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DNYWM.png" alt="allow insecure localhost in chrome settings" /></a> Refer to <a href="https://stackoverflow.com/questions/7580508/getting-chrome-to-accept-self-signed-localhost-certificate">this Stack Overflow</a> for more information. <hr /> This works, too: <ol> <li>See "Your connection is not private. blah-bla-blah"...</li> <li>Type "thisisunsafe" (key listeners pick it up).</li> </ol>

36,740,533

What are forward and backward passes in neural networks?

What is the meaning of forward pass and backward pass in neural networks? Everybody is mentioning these expressions when talking about backpropagation and epochs. I understood that forward pass and backward pass together form an epoch.

48,319,902

1

null

2016-04-20 10:10:19.927 UTC

12

2021-03-29 10:28:54.597 UTC

2017-10-17 19:33:23.287 UTC

null

3,924,118

null

5,343,790

null

1

39

neural-network|backpropagation|conv-neural-network

46,899

The "forward pass" refers to calculation process, values of the output layers from the inputs data. It's traversing through all neurons from first to last layer. A loss function is calculated from the output values. And then "backward pass" refers to process of counting changes in weights (de facto learning), using gradient descent algorithm (or similar). Computation is made from last layer, backward to the first layer. Backward and forward pass makes together one "iteration". <hr /> During one iteration, you usually pass a subset of the data set, which is called "mini-batch" or "batch" (however, "batch" can also mean an entire set, hence the prefix "mini") "Epoch" means passing the entire data set in batches. One epoch contains (number_of_items / batch_size) iterations