INSTRUCTION
stringlengths 1
46.3k
| RESPONSE
stringlengths 75
80.2k
|
|---|---|
Try to infer an object's dtype, for use in arithmetic ops
Uses `element.dtype` if that's available.
Objects implementing the iterator protocol are cast to a NumPy array,
and from there the array's type is used.
Parameters
----------
element : object
Possibly has a `.dtype` attribute, and possibly the iterator
protocol.
Returns
-------
tipo : type
Examples
--------
>>> from collections import namedtuple
>>> Foo = namedtuple("Foo", "dtype")
>>> maybe_infer_dtype_type(Foo(np.dtype("i8")))
numpy.int64 | def maybe_infer_dtype_type(element):
"""Try to infer an object's dtype, for use in arithmetic ops
Uses `element.dtype` if that's available.
Objects implementing the iterator protocol are cast to a NumPy array,
and from there the array's type is used.
Parameters
----------
element : object
Possibly has a `.dtype` attribute, and possibly the iterator
protocol.
Returns
-------
tipo : type
Examples
--------
>>> from collections import namedtuple
>>> Foo = namedtuple("Foo", "dtype")
>>> maybe_infer_dtype_type(Foo(np.dtype("i8")))
numpy.int64
"""
tipo = None
if hasattr(element, 'dtype'):
tipo = element.dtype
elif is_list_like(element):
element = np.asarray(element)
tipo = element.dtype
return tipo |
provide explicit type promotion and coercion
Parameters
----------
values : the ndarray that we want to maybe upcast
fill_value : what we want to fill with
dtype : if None, then use the dtype of the values, else coerce to this type
copy : if True always make a copy even if no upcast is required | def maybe_upcast(values, fill_value=np.nan, dtype=None, copy=False):
""" provide explicit type promotion and coercion
Parameters
----------
values : the ndarray that we want to maybe upcast
fill_value : what we want to fill with
dtype : if None, then use the dtype of the values, else coerce to this type
copy : if True always make a copy even if no upcast is required
"""
if is_extension_type(values):
if copy:
values = values.copy()
else:
if dtype is None:
dtype = values.dtype
new_dtype, fill_value = maybe_promote(dtype, fill_value)
if new_dtype != values.dtype:
values = values.astype(new_dtype)
elif copy:
values = values.copy()
return values, fill_value |
Change string like dtypes to object for
``DataFrame.select_dtypes()``. | def invalidate_string_dtypes(dtype_set):
"""Change string like dtypes to object for
``DataFrame.select_dtypes()``.
"""
non_string_dtypes = dtype_set - {np.dtype('S').type, np.dtype('<U').type}
if non_string_dtypes != dtype_set:
raise TypeError("string dtypes are not allowed, use 'object' instead") |
coerce the indexer input array to the smallest dtype possible | def coerce_indexer_dtype(indexer, categories):
""" coerce the indexer input array to the smallest dtype possible """
length = len(categories)
if length < _int8_max:
return ensure_int8(indexer)
elif length < _int16_max:
return ensure_int16(indexer)
elif length < _int32_max:
return ensure_int32(indexer)
return ensure_int64(indexer) |
given a dtypes and a result set, coerce the result elements to the
dtypes | def coerce_to_dtypes(result, dtypes):
"""
given a dtypes and a result set, coerce the result elements to the
dtypes
"""
if len(result) != len(dtypes):
raise AssertionError("_coerce_to_dtypes requires equal len arrays")
def conv(r, dtype):
try:
if isna(r):
pass
elif dtype == _NS_DTYPE:
r = tslibs.Timestamp(r)
elif dtype == _TD_DTYPE:
r = tslibs.Timedelta(r)
elif dtype == np.bool_:
# messy. non 0/1 integers do not get converted.
if is_integer(r) and r not in [0, 1]:
return int(r)
r = bool(r)
elif dtype.kind == 'f':
r = float(r)
elif dtype.kind == 'i':
r = int(r)
except Exception:
pass
return r
return [conv(r, dtype) for r, dtype in zip(result, dtypes)] |
Cast the elements of an array to a given dtype a nan-safe manner.
Parameters
----------
arr : ndarray
dtype : np.dtype
copy : bool, default True
If False, a view will be attempted but may fail, if
e.g. the item sizes don't align.
skipna: bool, default False
Whether or not we should skip NaN when casting as a string-type.
Raises
------
ValueError
The dtype was a datetime64/timedelta64 dtype, but it had no unit. | def astype_nansafe(arr, dtype, copy=True, skipna=False):
"""
Cast the elements of an array to a given dtype a nan-safe manner.
Parameters
----------
arr : ndarray
dtype : np.dtype
copy : bool, default True
If False, a view will be attempted but may fail, if
e.g. the item sizes don't align.
skipna: bool, default False
Whether or not we should skip NaN when casting as a string-type.
Raises
------
ValueError
The dtype was a datetime64/timedelta64 dtype, but it had no unit.
"""
# dispatch on extension dtype if needed
if is_extension_array_dtype(dtype):
return dtype.construct_array_type()._from_sequence(
arr, dtype=dtype, copy=copy)
if not isinstance(dtype, np.dtype):
dtype = pandas_dtype(dtype)
if issubclass(dtype.type, str):
return lib.astype_str(arr.ravel(),
skipna=skipna).reshape(arr.shape)
elif is_datetime64_dtype(arr):
if is_object_dtype(dtype):
return tslib.ints_to_pydatetime(arr.view(np.int64))
elif dtype == np.int64:
return arr.view(dtype)
# allow frequency conversions
if dtype.kind == 'M':
return arr.astype(dtype)
raise TypeError("cannot astype a datetimelike from [{from_dtype}] "
"to [{to_dtype}]".format(from_dtype=arr.dtype,
to_dtype=dtype))
elif is_timedelta64_dtype(arr):
if is_object_dtype(dtype):
return tslibs.ints_to_pytimedelta(arr.view(np.int64))
elif dtype == np.int64:
return arr.view(dtype)
if dtype not in [_INT64_DTYPE, _TD_DTYPE]:
# allow frequency conversions
# we return a float here!
if dtype.kind == 'm':
mask = isna(arr)
result = arr.astype(dtype).astype(np.float64)
result[mask] = np.nan
return result
elif dtype == _TD_DTYPE:
return arr.astype(_TD_DTYPE, copy=copy)
raise TypeError("cannot astype a timedelta from [{from_dtype}] "
"to [{to_dtype}]".format(from_dtype=arr.dtype,
to_dtype=dtype))
elif (np.issubdtype(arr.dtype, np.floating) and
np.issubdtype(dtype, np.integer)):
if not np.isfinite(arr).all():
raise ValueError('Cannot convert non-finite values (NA or inf) to '
'integer')
elif is_object_dtype(arr):
# work around NumPy brokenness, #1987
if np.issubdtype(dtype.type, np.integer):
return lib.astype_intsafe(arr.ravel(), dtype).reshape(arr.shape)
# if we have a datetime/timedelta array of objects
# then coerce to a proper dtype and recall astype_nansafe
elif is_datetime64_dtype(dtype):
from pandas import to_datetime
return astype_nansafe(to_datetime(arr).values, dtype, copy=copy)
elif is_timedelta64_dtype(dtype):
from pandas import to_timedelta
return astype_nansafe(to_timedelta(arr).values, dtype, copy=copy)
if dtype.name in ("datetime64", "timedelta64"):
msg = ("The '{dtype}' dtype has no unit. "
"Please pass in '{dtype}[ns]' instead.")
raise ValueError(msg.format(dtype=dtype.name))
if copy or is_object_dtype(arr) or is_object_dtype(dtype):
# Explicit copy, or required since NumPy can't view from / to object.
return arr.astype(dtype, copy=True)
return arr.view(dtype) |
if we have an object dtype, try to coerce dates and/or numbers | def maybe_convert_objects(values, convert_dates=True, convert_numeric=True,
convert_timedeltas=True, copy=True):
""" if we have an object dtype, try to coerce dates and/or numbers """
# if we have passed in a list or scalar
if isinstance(values, (list, tuple)):
values = np.array(values, dtype=np.object_)
if not hasattr(values, 'dtype'):
values = np.array([values], dtype=np.object_)
# convert dates
if convert_dates and values.dtype == np.object_:
# we take an aggressive stance and convert to datetime64[ns]
if convert_dates == 'coerce':
new_values = maybe_cast_to_datetime(
values, 'M8[ns]', errors='coerce')
# if we are all nans then leave me alone
if not isna(new_values).all():
values = new_values
else:
values = lib.maybe_convert_objects(values,
convert_datetime=convert_dates)
# convert timedeltas
if convert_timedeltas and values.dtype == np.object_:
if convert_timedeltas == 'coerce':
from pandas.core.tools.timedeltas import to_timedelta
new_values = to_timedelta(values, errors='coerce')
# if we are all nans then leave me alone
if not isna(new_values).all():
values = new_values
else:
values = lib.maybe_convert_objects(
values, convert_timedelta=convert_timedeltas)
# convert to numeric
if values.dtype == np.object_:
if convert_numeric:
try:
new_values = lib.maybe_convert_numeric(values, set(),
coerce_numeric=True)
# if we are all nans then leave me alone
if not isna(new_values).all():
values = new_values
except Exception:
pass
else:
# soft-conversion
values = lib.maybe_convert_objects(values)
values = values.copy() if copy else values
return values |
if we have an object dtype, try to coerce dates and/or numbers | def soft_convert_objects(values, datetime=True, numeric=True, timedelta=True,
coerce=False, copy=True):
""" if we have an object dtype, try to coerce dates and/or numbers """
conversion_count = sum((datetime, numeric, timedelta))
if conversion_count == 0:
raise ValueError('At least one of datetime, numeric or timedelta must '
'be True.')
elif conversion_count > 1 and coerce:
raise ValueError("Only one of 'datetime', 'numeric' or "
"'timedelta' can be True when when coerce=True.")
if isinstance(values, (list, tuple)):
# List or scalar
values = np.array(values, dtype=np.object_)
elif not hasattr(values, 'dtype'):
values = np.array([values], dtype=np.object_)
elif not is_object_dtype(values.dtype):
# If not object, do not attempt conversion
values = values.copy() if copy else values
return values
# If 1 flag is coerce, ensure 2 others are False
if coerce:
# Immediate return if coerce
if datetime:
from pandas import to_datetime
return to_datetime(values, errors='coerce').to_numpy()
elif timedelta:
from pandas import to_timedelta
return to_timedelta(values, errors='coerce').to_numpy()
elif numeric:
from pandas import to_numeric
return to_numeric(values, errors='coerce')
# Soft conversions
if datetime:
# GH 20380, when datetime is beyond year 2262, hence outside
# bound of nanosecond-resolution 64-bit integers.
try:
values = lib.maybe_convert_objects(values,
convert_datetime=datetime)
except OutOfBoundsDatetime:
pass
if timedelta and is_object_dtype(values.dtype):
# Object check to ensure only run if previous did not convert
values = lib.maybe_convert_objects(values, convert_timedelta=timedelta)
if numeric and is_object_dtype(values.dtype):
try:
converted = lib.maybe_convert_numeric(values, set(),
coerce_numeric=True)
# If all NaNs, then do not-alter
values = converted if not isna(converted).all() else values
values = values.copy() if copy else values
except Exception:
pass
return values |
we might have a array (or single object) that is datetime like,
and no dtype is passed don't change the value unless we find a
datetime/timedelta set
this is pretty strict in that a datetime/timedelta is REQUIRED
in addition to possible nulls/string likes
Parameters
----------
value : np.array / Series / Index / list-like
convert_dates : boolean, default False
if True try really hard to convert dates (such as datetime.date), other
leave inferred dtype 'date' alone | def maybe_infer_to_datetimelike(value, convert_dates=False):
"""
we might have a array (or single object) that is datetime like,
and no dtype is passed don't change the value unless we find a
datetime/timedelta set
this is pretty strict in that a datetime/timedelta is REQUIRED
in addition to possible nulls/string likes
Parameters
----------
value : np.array / Series / Index / list-like
convert_dates : boolean, default False
if True try really hard to convert dates (such as datetime.date), other
leave inferred dtype 'date' alone
"""
# TODO: why not timedelta?
if isinstance(value, (ABCDatetimeIndex, ABCPeriodIndex,
ABCDatetimeArray, ABCPeriodArray)):
return value
elif isinstance(value, ABCSeries):
if isinstance(value._values, ABCDatetimeIndex):
return value._values
v = value
if not is_list_like(v):
v = [v]
v = np.array(v, copy=False)
# we only care about object dtypes
if not is_object_dtype(v):
return value
shape = v.shape
if not v.ndim == 1:
v = v.ravel()
if not len(v):
return value
def try_datetime(v):
# safe coerce to datetime64
try:
# GH19671
v = tslib.array_to_datetime(v,
require_iso8601=True,
errors='raise')[0]
except ValueError:
# we might have a sequence of the same-datetimes with tz's
# if so coerce to a DatetimeIndex; if they are not the same,
# then these stay as object dtype, xref GH19671
try:
from pandas._libs.tslibs import conversion
from pandas import DatetimeIndex
values, tz = conversion.datetime_to_datetime64(v)
return DatetimeIndex(values).tz_localize(
'UTC').tz_convert(tz=tz)
except (ValueError, TypeError):
pass
except Exception:
pass
return v.reshape(shape)
def try_timedelta(v):
# safe coerce to timedelta64
# will try first with a string & object conversion
from pandas import to_timedelta
try:
return to_timedelta(v)._ndarray_values.reshape(shape)
except Exception:
return v.reshape(shape)
inferred_type = lib.infer_datetimelike_array(ensure_object(v))
if inferred_type == 'date' and convert_dates:
value = try_datetime(v)
elif inferred_type == 'datetime':
value = try_datetime(v)
elif inferred_type == 'timedelta':
value = try_timedelta(v)
elif inferred_type == 'nat':
# if all NaT, return as datetime
if isna(v).all():
value = try_datetime(v)
else:
# We have at least a NaT and a string
# try timedelta first to avoid spurious datetime conversions
# e.g. '00:00:01' is a timedelta but technically is also a datetime
value = try_timedelta(v)
if lib.infer_dtype(value, skipna=False) in ['mixed']:
# cannot skip missing values, as NaT implies that the string
# is actually a datetime
value = try_datetime(v)
return value |
Find a common data type among the given dtypes.
Parameters
----------
types : list of dtypes
Returns
-------
pandas extension or numpy dtype
See Also
--------
numpy.find_common_type | def find_common_type(types):
"""
Find a common data type among the given dtypes.
Parameters
----------
types : list of dtypes
Returns
-------
pandas extension or numpy dtype
See Also
--------
numpy.find_common_type
"""
if len(types) == 0:
raise ValueError('no types given')
first = types[0]
# workaround for find_common_type([np.dtype('datetime64[ns]')] * 2)
# => object
if all(is_dtype_equal(first, t) for t in types[1:]):
return first
if any(isinstance(t, (PandasExtensionDtype, ExtensionDtype))
for t in types):
return np.object
# take lowest unit
if all(is_datetime64_dtype(t) for t in types):
return np.dtype('datetime64[ns]')
if all(is_timedelta64_dtype(t) for t in types):
return np.dtype('timedelta64[ns]')
# don't mix bool / int or float or complex
# this is different from numpy, which casts bool with float/int as int
has_bools = any(is_bool_dtype(t) for t in types)
if has_bools:
for t in types:
if is_integer_dtype(t) or is_float_dtype(t) or is_complex_dtype(t):
return np.object
return np.find_common_type(types, []) |
create np.ndarray of specified shape and dtype, filled with values
Parameters
----------
shape : tuple
value : scalar value
dtype : np.dtype, optional
dtype to coerce
Returns
-------
ndarray of shape, filled with value, of specified / inferred dtype | def cast_scalar_to_array(shape, value, dtype=None):
"""
create np.ndarray of specified shape and dtype, filled with values
Parameters
----------
shape : tuple
value : scalar value
dtype : np.dtype, optional
dtype to coerce
Returns
-------
ndarray of shape, filled with value, of specified / inferred dtype
"""
if dtype is None:
dtype, fill_value = infer_dtype_from_scalar(value)
else:
fill_value = value
values = np.empty(shape, dtype=dtype)
values.fill(fill_value)
return values |
create a np.ndarray / pandas type of specified shape and dtype
filled with values
Parameters
----------
value : scalar value
length : int
dtype : pandas_dtype / np.dtype
Returns
-------
np.ndarray / pandas type of length, filled with value | def construct_1d_arraylike_from_scalar(value, length, dtype):
"""
create a np.ndarray / pandas type of specified shape and dtype
filled with values
Parameters
----------
value : scalar value
length : int
dtype : pandas_dtype / np.dtype
Returns
-------
np.ndarray / pandas type of length, filled with value
"""
if is_datetime64tz_dtype(dtype):
from pandas import DatetimeIndex
subarr = DatetimeIndex([value] * length, dtype=dtype)
elif is_categorical_dtype(dtype):
from pandas import Categorical
subarr = Categorical([value] * length, dtype=dtype)
else:
if not isinstance(dtype, (np.dtype, type(np.dtype))):
dtype = dtype.dtype
if length and is_integer_dtype(dtype) and isna(value):
# coerce if we have nan for an integer dtype
dtype = np.dtype('float64')
elif isinstance(dtype, np.dtype) and dtype.kind in ("U", "S"):
# we need to coerce to object dtype to avoid
# to allow numpy to take our string as a scalar value
dtype = object
if not isna(value):
value = to_str(value)
subarr = np.empty(length, dtype=dtype)
subarr.fill(value)
return subarr |
Transform any list-like object in a 1-dimensional numpy array of object
dtype.
Parameters
----------
values : any iterable which has a len()
Raises
------
TypeError
* If `values` does not have a len()
Returns
-------
1-dimensional numpy array of dtype object | def construct_1d_object_array_from_listlike(values):
"""
Transform any list-like object in a 1-dimensional numpy array of object
dtype.
Parameters
----------
values : any iterable which has a len()
Raises
------
TypeError
* If `values` does not have a len()
Returns
-------
1-dimensional numpy array of dtype object
"""
# numpy will try to interpret nested lists as further dimensions, hence
# making a 1D array that contains list-likes is a bit tricky:
result = np.empty(len(values), dtype='object')
result[:] = values
return result |
Construct a new ndarray, coercing `values` to `dtype`, preserving NA.
Parameters
----------
values : Sequence
dtype : numpy.dtype, optional
copy : bool, default False
Note that copies may still be made with ``copy=False`` if casting
is required.
Returns
-------
arr : ndarray[dtype]
Examples
--------
>>> np.array([1.0, 2.0, None], dtype='str')
array(['1.0', '2.0', 'None'], dtype='<U4')
>>> construct_1d_ndarray_preserving_na([1.0, 2.0, None], dtype='str') | def construct_1d_ndarray_preserving_na(values, dtype=None, copy=False):
"""
Construct a new ndarray, coercing `values` to `dtype`, preserving NA.
Parameters
----------
values : Sequence
dtype : numpy.dtype, optional
copy : bool, default False
Note that copies may still be made with ``copy=False`` if casting
is required.
Returns
-------
arr : ndarray[dtype]
Examples
--------
>>> np.array([1.0, 2.0, None], dtype='str')
array(['1.0', '2.0', 'None'], dtype='<U4')
>>> construct_1d_ndarray_preserving_na([1.0, 2.0, None], dtype='str')
"""
subarr = np.array(values, dtype=dtype, copy=copy)
if dtype is not None and dtype.kind in ("U", "S"):
# GH-21083
# We can't just return np.array(subarr, dtype='str') since
# NumPy will convert the non-string objects into strings
# Including NA values. Se we have to go
# string -> object -> update NA, which requires an
# additional pass over the data.
na_values = isna(values)
subarr2 = subarr.astype(object)
subarr2[na_values] = np.asarray(values, dtype=object)[na_values]
subarr = subarr2
return subarr |
Takes any dtype and returns the casted version, raising for when data is
incompatible with integer/unsigned integer dtypes.
.. versionadded:: 0.24.0
Parameters
----------
arr : array-like
The array to cast.
dtype : str, np.dtype
The integer dtype to cast the array to.
copy: boolean, default False
Whether to make a copy of the array before returning.
Returns
-------
int_arr : ndarray
An array of integer or unsigned integer dtype
Raises
------
OverflowError : the dtype is incompatible with the data
ValueError : loss of precision has occurred during casting
Examples
--------
If you try to coerce negative values to unsigned integers, it raises:
>>> Series([-1], dtype="uint64")
Traceback (most recent call last):
...
OverflowError: Trying to coerce negative values to unsigned integers
Also, if you try to coerce float values to integers, it raises:
>>> Series([1, 2, 3.5], dtype="int64")
Traceback (most recent call last):
...
ValueError: Trying to coerce float values to integers | def maybe_cast_to_integer_array(arr, dtype, copy=False):
"""
Takes any dtype and returns the casted version, raising for when data is
incompatible with integer/unsigned integer dtypes.
.. versionadded:: 0.24.0
Parameters
----------
arr : array-like
The array to cast.
dtype : str, np.dtype
The integer dtype to cast the array to.
copy: boolean, default False
Whether to make a copy of the array before returning.
Returns
-------
int_arr : ndarray
An array of integer or unsigned integer dtype
Raises
------
OverflowError : the dtype is incompatible with the data
ValueError : loss of precision has occurred during casting
Examples
--------
If you try to coerce negative values to unsigned integers, it raises:
>>> Series([-1], dtype="uint64")
Traceback (most recent call last):
...
OverflowError: Trying to coerce negative values to unsigned integers
Also, if you try to coerce float values to integers, it raises:
>>> Series([1, 2, 3.5], dtype="int64")
Traceback (most recent call last):
...
ValueError: Trying to coerce float values to integers
"""
try:
if not hasattr(arr, "astype"):
casted = np.array(arr, dtype=dtype, copy=copy)
else:
casted = arr.astype(dtype, copy=copy)
except OverflowError:
raise OverflowError("The elements provided in the data cannot all be "
"casted to the dtype {dtype}".format(dtype=dtype))
if np.array_equal(arr, casted):
return casted
# We do this casting to allow for proper
# data and dtype checking.
#
# We didn't do this earlier because NumPy
# doesn't handle `uint64` correctly.
arr = np.asarray(arr)
if is_unsigned_integer_dtype(dtype) and (arr < 0).any():
raise OverflowError("Trying to coerce negative values "
"to unsigned integers")
if is_integer_dtype(dtype) and (is_float_dtype(arr) or
is_object_dtype(arr)):
raise ValueError("Trying to coerce float values to integers") |
Make a scatter plot from two DataFrame columns
Parameters
----------
data : DataFrame
x : Column name for the x-axis values
y : Column name for the y-axis values
ax : Matplotlib axis object
figsize : A tuple (width, height) in inches
grid : Setting this to True will show the grid
kwargs : other plotting keyword arguments
To be passed to scatter function
Returns
-------
matplotlib.Figure | def scatter_plot(data, x, y, by=None, ax=None, figsize=None, grid=False,
**kwargs):
"""
Make a scatter plot from two DataFrame columns
Parameters
----------
data : DataFrame
x : Column name for the x-axis values
y : Column name for the y-axis values
ax : Matplotlib axis object
figsize : A tuple (width, height) in inches
grid : Setting this to True will show the grid
kwargs : other plotting keyword arguments
To be passed to scatter function
Returns
-------
matplotlib.Figure
"""
import matplotlib.pyplot as plt
kwargs.setdefault('edgecolors', 'none')
def plot_group(group, ax):
xvals = group[x].values
yvals = group[y].values
ax.scatter(xvals, yvals, **kwargs)
ax.grid(grid)
if by is not None:
fig = _grouped_plot(plot_group, data, by=by, figsize=figsize, ax=ax)
else:
if ax is None:
fig = plt.figure()
ax = fig.add_subplot(111)
else:
fig = ax.get_figure()
plot_group(data, ax)
ax.set_ylabel(pprint_thing(y))
ax.set_xlabel(pprint_thing(x))
ax.grid(grid)
return fig |
Grouped histogram
Parameters
----------
data : Series/DataFrame
column : object, optional
by : object, optional
ax : axes, optional
bins : int, default 50
figsize : tuple, optional
layout : optional
sharex : bool, default False
sharey : bool, default False
rot : int, default 90
grid : bool, default True
kwargs : dict, keyword arguments passed to matplotlib.Axes.hist
Returns
-------
collection of Matplotlib Axes | def grouped_hist(data, column=None, by=None, ax=None, bins=50, figsize=None,
layout=None, sharex=False, sharey=False, rot=90, grid=True,
xlabelsize=None, xrot=None, ylabelsize=None, yrot=None,
**kwargs):
"""
Grouped histogram
Parameters
----------
data : Series/DataFrame
column : object, optional
by : object, optional
ax : axes, optional
bins : int, default 50
figsize : tuple, optional
layout : optional
sharex : bool, default False
sharey : bool, default False
rot : int, default 90
grid : bool, default True
kwargs : dict, keyword arguments passed to matplotlib.Axes.hist
Returns
-------
collection of Matplotlib Axes
"""
_raise_if_no_mpl()
_converter._WARN = False
def plot_group(group, ax):
ax.hist(group.dropna().values, bins=bins, **kwargs)
xrot = xrot or rot
fig, axes = _grouped_plot(plot_group, data, column=column,
by=by, sharex=sharex, sharey=sharey, ax=ax,
figsize=figsize, layout=layout, rot=rot)
_set_ticks_props(axes, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot)
fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1, right=0.9,
hspace=0.5, wspace=0.3)
return axes |
Draw histogram of the input series using matplotlib.
Parameters
----------
by : object, optional
If passed, then used to form histograms for separate groups
ax : matplotlib axis object
If not passed, uses gca()
grid : bool, default True
Whether to show axis grid lines
xlabelsize : int, default None
If specified changes the x-axis label size
xrot : float, default None
rotation of x axis labels
ylabelsize : int, default None
If specified changes the y-axis label size
yrot : float, default None
rotation of y axis labels
figsize : tuple, default None
figure size in inches by default
bins : integer or sequence, default 10
Number of histogram bins to be used. If an integer is given, bins + 1
bin edges are calculated and returned. If bins is a sequence, gives
bin edges, including left edge of first bin and right edge of last
bin. In this case, bins is returned unmodified.
bins : integer, default 10
Number of histogram bins to be used
`**kwds` : keywords
To be passed to the actual plotting function
See Also
--------
matplotlib.axes.Axes.hist : Plot a histogram using matplotlib. | def hist_series(self, by=None, ax=None, grid=True, xlabelsize=None,
xrot=None, ylabelsize=None, yrot=None, figsize=None,
bins=10, **kwds):
"""
Draw histogram of the input series using matplotlib.
Parameters
----------
by : object, optional
If passed, then used to form histograms for separate groups
ax : matplotlib axis object
If not passed, uses gca()
grid : bool, default True
Whether to show axis grid lines
xlabelsize : int, default None
If specified changes the x-axis label size
xrot : float, default None
rotation of x axis labels
ylabelsize : int, default None
If specified changes the y-axis label size
yrot : float, default None
rotation of y axis labels
figsize : tuple, default None
figure size in inches by default
bins : integer or sequence, default 10
Number of histogram bins to be used. If an integer is given, bins + 1
bin edges are calculated and returned. If bins is a sequence, gives
bin edges, including left edge of first bin and right edge of last
bin. In this case, bins is returned unmodified.
bins : integer, default 10
Number of histogram bins to be used
`**kwds` : keywords
To be passed to the actual plotting function
See Also
--------
matplotlib.axes.Axes.hist : Plot a histogram using matplotlib.
"""
import matplotlib.pyplot as plt
if by is None:
if kwds.get('layout', None) is not None:
raise ValueError("The 'layout' keyword is not supported when "
"'by' is None")
# hack until the plotting interface is a bit more unified
fig = kwds.pop('figure', plt.gcf() if plt.get_fignums() else
plt.figure(figsize=figsize))
if (figsize is not None and tuple(figsize) !=
tuple(fig.get_size_inches())):
fig.set_size_inches(*figsize, forward=True)
if ax is None:
ax = fig.gca()
elif ax.get_figure() != fig:
raise AssertionError('passed axis not bound to passed figure')
values = self.dropna().values
ax.hist(values, bins=bins, **kwds)
ax.grid(grid)
axes = np.array([ax])
_set_ticks_props(axes, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot)
else:
if 'figure' in kwds:
raise ValueError("Cannot pass 'figure' when using the "
"'by' argument, since a new 'Figure' instance "
"will be created")
axes = grouped_hist(self, by=by, ax=ax, grid=grid, figsize=figsize,
bins=bins, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot, **kwds)
if hasattr(axes, 'ndim'):
if axes.ndim == 1 and len(axes) == 1:
return axes[0]
return axes |
Make box plots from DataFrameGroupBy data.
Parameters
----------
grouped : Grouped DataFrame
subplots : bool
* ``False`` - no subplots will be used
* ``True`` - create a subplot for each group
column : column name or list of names, or vector
Can be any valid input to groupby
fontsize : int or string
rot : label rotation angle
grid : Setting this to True will show the grid
ax : Matplotlib axis object, default None
figsize : A tuple (width, height) in inches
layout : tuple (optional)
(rows, columns) for the layout of the plot
sharex : bool, default False
Whether x-axes will be shared among subplots
.. versionadded:: 0.23.1
sharey : bool, default True
Whether y-axes will be shared among subplots
.. versionadded:: 0.23.1
`**kwds` : Keyword Arguments
All other plotting keyword arguments to be passed to
matplotlib's boxplot function
Returns
-------
dict of key/value = group key/DataFrame.boxplot return value
or DataFrame.boxplot return value in case subplots=figures=False
Examples
--------
>>> import itertools
>>> tuples = [t for t in itertools.product(range(1000), range(4))]
>>> index = pd.MultiIndex.from_tuples(tuples, names=['lvl0', 'lvl1'])
>>> data = np.random.randn(len(index),4)
>>> df = pd.DataFrame(data, columns=list('ABCD'), index=index)
>>>
>>> grouped = df.groupby(level='lvl1')
>>> boxplot_frame_groupby(grouped)
>>>
>>> grouped = df.unstack(level='lvl1').groupby(level=0, axis=1)
>>> boxplot_frame_groupby(grouped, subplots=False) | def boxplot_frame_groupby(grouped, subplots=True, column=None, fontsize=None,
rot=0, grid=True, ax=None, figsize=None,
layout=None, sharex=False, sharey=True, **kwds):
"""
Make box plots from DataFrameGroupBy data.
Parameters
----------
grouped : Grouped DataFrame
subplots : bool
* ``False`` - no subplots will be used
* ``True`` - create a subplot for each group
column : column name or list of names, or vector
Can be any valid input to groupby
fontsize : int or string
rot : label rotation angle
grid : Setting this to True will show the grid
ax : Matplotlib axis object, default None
figsize : A tuple (width, height) in inches
layout : tuple (optional)
(rows, columns) for the layout of the plot
sharex : bool, default False
Whether x-axes will be shared among subplots
.. versionadded:: 0.23.1
sharey : bool, default True
Whether y-axes will be shared among subplots
.. versionadded:: 0.23.1
`**kwds` : Keyword Arguments
All other plotting keyword arguments to be passed to
matplotlib's boxplot function
Returns
-------
dict of key/value = group key/DataFrame.boxplot return value
or DataFrame.boxplot return value in case subplots=figures=False
Examples
--------
>>> import itertools
>>> tuples = [t for t in itertools.product(range(1000), range(4))]
>>> index = pd.MultiIndex.from_tuples(tuples, names=['lvl0', 'lvl1'])
>>> data = np.random.randn(len(index),4)
>>> df = pd.DataFrame(data, columns=list('ABCD'), index=index)
>>>
>>> grouped = df.groupby(level='lvl1')
>>> boxplot_frame_groupby(grouped)
>>>
>>> grouped = df.unstack(level='lvl1').groupby(level=0, axis=1)
>>> boxplot_frame_groupby(grouped, subplots=False)
"""
_raise_if_no_mpl()
_converter._WARN = False
if subplots is True:
naxes = len(grouped)
fig, axes = _subplots(naxes=naxes, squeeze=False,
ax=ax, sharex=sharex, sharey=sharey,
figsize=figsize, layout=layout)
axes = _flatten(axes)
from pandas.core.series import Series
ret = Series()
for (key, group), ax in zip(grouped, axes):
d = group.boxplot(ax=ax, column=column, fontsize=fontsize,
rot=rot, grid=grid, **kwds)
ax.set_title(pprint_thing(key))
ret.loc[key] = d
fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1,
right=0.9, wspace=0.2)
else:
from pandas.core.reshape.concat import concat
keys, frames = zip(*grouped)
if grouped.axis == 0:
df = concat(frames, keys=keys, axis=1)
else:
if len(frames) > 1:
df = frames[0].join(frames[1::])
else:
df = frames[0]
ret = df.boxplot(column=column, fontsize=fontsize, rot=rot,
grid=grid, ax=ax, figsize=figsize,
layout=layout, **kwds)
return ret |
check whether ax has data | def _has_plotted_object(self, ax):
"""check whether ax has data"""
return (len(ax.lines) != 0 or
len(ax.artists) != 0 or
len(ax.containers) != 0) |
Return result axes | def result(self):
"""
Return result axes
"""
if self.subplots:
if self.layout is not None and not is_list_like(self.ax):
return self.axes.reshape(*self.layout)
else:
return self.axes
else:
sec_true = isinstance(self.secondary_y, bool) and self.secondary_y
all_sec = (is_list_like(self.secondary_y) and
len(self.secondary_y) == self.nseries)
if (sec_true or all_sec):
# if all data is plotted on secondary, return right axes
return self._get_ax_layer(self.axes[0], primary=False)
else:
return self.axes[0] |
Common post process for each axes | def _post_plot_logic_common(self, ax, data):
"""Common post process for each axes"""
def get_label(i):
try:
return pprint_thing(data.index[i])
except Exception:
return ''
if self.orientation == 'vertical' or self.orientation is None:
if self._need_to_set_index:
xticklabels = [get_label(x) for x in ax.get_xticks()]
ax.set_xticklabels(xticklabels)
self._apply_axis_properties(ax.xaxis, rot=self.rot,
fontsize=self.fontsize)
self._apply_axis_properties(ax.yaxis, fontsize=self.fontsize)
if hasattr(ax, 'right_ax'):
self._apply_axis_properties(ax.right_ax.yaxis,
fontsize=self.fontsize)
elif self.orientation == 'horizontal':
if self._need_to_set_index:
yticklabels = [get_label(y) for y in ax.get_yticks()]
ax.set_yticklabels(yticklabels)
self._apply_axis_properties(ax.yaxis, rot=self.rot,
fontsize=self.fontsize)
self._apply_axis_properties(ax.xaxis, fontsize=self.fontsize)
if hasattr(ax, 'right_ax'):
self._apply_axis_properties(ax.right_ax.yaxis,
fontsize=self.fontsize)
else: # pragma no cover
raise ValueError |
Common post process unrelated to data | def _adorn_subplots(self):
"""Common post process unrelated to data"""
if len(self.axes) > 0:
all_axes = self._get_subplots()
nrows, ncols = self._get_axes_layout()
_handle_shared_axes(axarr=all_axes, nplots=len(all_axes),
naxes=nrows * ncols, nrows=nrows,
ncols=ncols, sharex=self.sharex,
sharey=self.sharey)
for ax in self.axes:
if self.yticks is not None:
ax.set_yticks(self.yticks)
if self.xticks is not None:
ax.set_xticks(self.xticks)
if self.ylim is not None:
ax.set_ylim(self.ylim)
if self.xlim is not None:
ax.set_xlim(self.xlim)
ax.grid(self.grid)
if self.title:
if self.subplots:
if is_list_like(self.title):
if len(self.title) != self.nseries:
msg = ('The length of `title` must equal the number '
'of columns if using `title` of type `list` '
'and `subplots=True`.\n'
'length of title = {}\n'
'number of columns = {}').format(
len(self.title), self.nseries)
raise ValueError(msg)
for (ax, title) in zip(self.axes, self.title):
ax.set_title(title)
else:
self.fig.suptitle(self.title)
else:
if is_list_like(self.title):
msg = ('Using `title` of type `list` is not supported '
'unless `subplots=True` is passed')
raise ValueError(msg)
self.axes[0].set_title(self.title) |
Tick creation within matplotlib is reasonably expensive and is
internally deferred until accessed as Ticks are created/destroyed
multiple times per draw. It's therefore beneficial for us to avoid
accessing unless we will act on the Tick. | def _apply_axis_properties(self, axis, rot=None, fontsize=None):
""" Tick creation within matplotlib is reasonably expensive and is
internally deferred until accessed as Ticks are created/destroyed
multiple times per draw. It's therefore beneficial for us to avoid
accessing unless we will act on the Tick.
"""
if rot is not None or fontsize is not None:
# rot=0 is a valid setting, hence the explicit None check
labels = axis.get_majorticklabels() + axis.get_minorticklabels()
for label in labels:
if rot is not None:
label.set_rotation(rot)
if fontsize is not None:
label.set_fontsize(fontsize) |
get left (primary) or right (secondary) axes | def _get_ax_layer(cls, ax, primary=True):
"""get left (primary) or right (secondary) axes"""
if primary:
return getattr(ax, 'left_ax', ax)
else:
return getattr(ax, 'right_ax', ax) |
Manage style and color based on column number and its label.
Returns tuple of appropriate style and kwds which "color" may be added. | def _apply_style_colors(self, colors, kwds, col_num, label):
"""
Manage style and color based on column number and its label.
Returns tuple of appropriate style and kwds which "color" may be added.
"""
style = None
if self.style is not None:
if isinstance(self.style, list):
try:
style = self.style[col_num]
except IndexError:
pass
elif isinstance(self.style, dict):
style = self.style.get(label, style)
else:
style = self.style
has_color = 'color' in kwds or self.colormap is not None
nocolor_style = style is None or re.match('[a-z]+', style) is None
if (has_color or self.subplots) and nocolor_style:
kwds['color'] = colors[col_num % len(colors)]
return style, kwds |
Look for error keyword arguments and return the actual errorbar data
or return the error DataFrame/dict
Error bars can be specified in several ways:
Series: the user provides a pandas.Series object of the same
length as the data
ndarray: provides a np.ndarray of the same length as the data
DataFrame/dict: error values are paired with keys matching the
key in the plotted DataFrame
str: the name of the column within the plotted DataFrame | def _parse_errorbars(self, label, err):
"""
Look for error keyword arguments and return the actual errorbar data
or return the error DataFrame/dict
Error bars can be specified in several ways:
Series: the user provides a pandas.Series object of the same
length as the data
ndarray: provides a np.ndarray of the same length as the data
DataFrame/dict: error values are paired with keys matching the
key in the plotted DataFrame
str: the name of the column within the plotted DataFrame
"""
if err is None:
return None
def match_labels(data, e):
e = e.reindex(data.index)
return e
# key-matched DataFrame
if isinstance(err, ABCDataFrame):
err = match_labels(self.data, err)
# key-matched dict
elif isinstance(err, dict):
pass
# Series of error values
elif isinstance(err, ABCSeries):
# broadcast error series across data
err = match_labels(self.data, err)
err = np.atleast_2d(err)
err = np.tile(err, (self.nseries, 1))
# errors are a column in the dataframe
elif isinstance(err, str):
evalues = self.data[err].values
self.data = self.data[self.data.columns.drop(err)]
err = np.atleast_2d(evalues)
err = np.tile(err, (self.nseries, 1))
elif is_list_like(err):
if is_iterator(err):
err = np.atleast_2d(list(err))
else:
# raw error values
err = np.atleast_2d(err)
err_shape = err.shape
# asymmetrical error bars
if err.ndim == 3:
if (err_shape[0] != self.nseries) or \
(err_shape[1] != 2) or \
(err_shape[2] != len(self.data)):
msg = "Asymmetrical error bars should be provided " + \
"with the shape (%u, 2, %u)" % \
(self.nseries, len(self.data))
raise ValueError(msg)
# broadcast errors to each data series
if len(err) == 1:
err = np.tile(err, (self.nseries, 1))
elif is_number(err):
err = np.tile([err], (self.nseries, len(self.data)))
else:
msg = "No valid {label} detected".format(label=label)
raise ValueError(msg)
return err |
merge BoxPlot/KdePlot properties to passed kwds | def _make_plot_keywords(self, kwds, y):
"""merge BoxPlot/KdePlot properties to passed kwds"""
# y is required for KdePlot
kwds['bottom'] = self.bottom
kwds['bins'] = self.bins
return kwds |
Plot DataFrame columns as lines.
This function is useful to plot lines using DataFrame's values
as coordinates.
Parameters
----------
x : int or str, optional
Columns to use for the horizontal axis.
Either the location or the label of the columns to be used.
By default, it will use the DataFrame indices.
y : int, str, or list of them, optional
The values to be plotted.
Either the location or the label of the columns to be used.
By default, it will use the remaining DataFrame numeric columns.
**kwds
Keyword arguments to pass on to :meth:`DataFrame.plot`.
Returns
-------
:class:`matplotlib.axes.Axes` or :class:`numpy.ndarray`
Return an ndarray when ``subplots=True``.
See Also
--------
matplotlib.pyplot.plot : Plot y versus x as lines and/or markers.
Examples
--------
.. plot::
:context: close-figs
The following example shows the populations for some animals
over the years.
>>> df = pd.DataFrame({
... 'pig': [20, 18, 489, 675, 1776],
... 'horse': [4, 25, 281, 600, 1900]
... }, index=[1990, 1997, 2003, 2009, 2014])
>>> lines = df.plot.line()
.. plot::
:context: close-figs
An example with subplots, so an array of axes is returned.
>>> axes = df.plot.line(subplots=True)
>>> type(axes)
<class 'numpy.ndarray'>
.. plot::
:context: close-figs
The following example shows the relationship between both
populations.
>>> lines = df.plot.line(x='pig', y='horse') | def line(self, x=None, y=None, **kwds):
"""
Plot DataFrame columns as lines.
This function is useful to plot lines using DataFrame's values
as coordinates.
Parameters
----------
x : int or str, optional
Columns to use for the horizontal axis.
Either the location or the label of the columns to be used.
By default, it will use the DataFrame indices.
y : int, str, or list of them, optional
The values to be plotted.
Either the location or the label of the columns to be used.
By default, it will use the remaining DataFrame numeric columns.
**kwds
Keyword arguments to pass on to :meth:`DataFrame.plot`.
Returns
-------
:class:`matplotlib.axes.Axes` or :class:`numpy.ndarray`
Return an ndarray when ``subplots=True``.
See Also
--------
matplotlib.pyplot.plot : Plot y versus x as lines and/or markers.
Examples
--------
.. plot::
:context: close-figs
The following example shows the populations for some animals
over the years.
>>> df = pd.DataFrame({
... 'pig': [20, 18, 489, 675, 1776],
... 'horse': [4, 25, 281, 600, 1900]
... }, index=[1990, 1997, 2003, 2009, 2014])
>>> lines = df.plot.line()
.. plot::
:context: close-figs
An example with subplots, so an array of axes is returned.
>>> axes = df.plot.line(subplots=True)
>>> type(axes)
<class 'numpy.ndarray'>
.. plot::
:context: close-figs
The following example shows the relationship between both
populations.
>>> lines = df.plot.line(x='pig', y='horse')
"""
return self(kind='line', x=x, y=y, **kwds) |
Vertical bar plot.
A bar plot is a plot that presents categorical data with
rectangular bars with lengths proportional to the values that they
represent. A bar plot shows comparisons among discrete categories. One
axis of the plot shows the specific categories being compared, and the
other axis represents a measured value.
Parameters
----------
x : label or position, optional
Allows plotting of one column versus another. If not specified,
the index of the DataFrame is used.
y : label or position, optional
Allows plotting of one column versus another. If not specified,
all numerical columns are used.
**kwds
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
matplotlib.axes.Axes or np.ndarray of them
An ndarray is returned with one :class:`matplotlib.axes.Axes`
per column when ``subplots=True``.
See Also
--------
DataFrame.plot.barh : Horizontal bar plot.
DataFrame.plot : Make plots of a DataFrame.
matplotlib.pyplot.bar : Make a bar plot with matplotlib.
Examples
--------
Basic plot.
.. plot::
:context: close-figs
>>> df = pd.DataFrame({'lab':['A', 'B', 'C'], 'val':[10, 30, 20]})
>>> ax = df.plot.bar(x='lab', y='val', rot=0)
Plot a whole dataframe to a bar plot. Each column is assigned a
distinct color, and each row is nested in a group along the
horizontal axis.
.. plot::
:context: close-figs
>>> speed = [0.1, 17.5, 40, 48, 52, 69, 88]
>>> lifespan = [2, 8, 70, 1.5, 25, 12, 28]
>>> index = ['snail', 'pig', 'elephant',
... 'rabbit', 'giraffe', 'coyote', 'horse']
>>> df = pd.DataFrame({'speed': speed,
... 'lifespan': lifespan}, index=index)
>>> ax = df.plot.bar(rot=0)
Instead of nesting, the figure can be split by column with
``subplots=True``. In this case, a :class:`numpy.ndarray` of
:class:`matplotlib.axes.Axes` are returned.
.. plot::
:context: close-figs
>>> axes = df.plot.bar(rot=0, subplots=True)
>>> axes[1].legend(loc=2) # doctest: +SKIP
Plot a single column.
.. plot::
:context: close-figs
>>> ax = df.plot.bar(y='speed', rot=0)
Plot only selected categories for the DataFrame.
.. plot::
:context: close-figs
>>> ax = df.plot.bar(x='lifespan', rot=0) | def bar(self, x=None, y=None, **kwds):
"""
Vertical bar plot.
A bar plot is a plot that presents categorical data with
rectangular bars with lengths proportional to the values that they
represent. A bar plot shows comparisons among discrete categories. One
axis of the plot shows the specific categories being compared, and the
other axis represents a measured value.
Parameters
----------
x : label or position, optional
Allows plotting of one column versus another. If not specified,
the index of the DataFrame is used.
y : label or position, optional
Allows plotting of one column versus another. If not specified,
all numerical columns are used.
**kwds
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
matplotlib.axes.Axes or np.ndarray of them
An ndarray is returned with one :class:`matplotlib.axes.Axes`
per column when ``subplots=True``.
See Also
--------
DataFrame.plot.barh : Horizontal bar plot.
DataFrame.plot : Make plots of a DataFrame.
matplotlib.pyplot.bar : Make a bar plot with matplotlib.
Examples
--------
Basic plot.
.. plot::
:context: close-figs
>>> df = pd.DataFrame({'lab':['A', 'B', 'C'], 'val':[10, 30, 20]})
>>> ax = df.plot.bar(x='lab', y='val', rot=0)
Plot a whole dataframe to a bar plot. Each column is assigned a
distinct color, and each row is nested in a group along the
horizontal axis.
.. plot::
:context: close-figs
>>> speed = [0.1, 17.5, 40, 48, 52, 69, 88]
>>> lifespan = [2, 8, 70, 1.5, 25, 12, 28]
>>> index = ['snail', 'pig', 'elephant',
... 'rabbit', 'giraffe', 'coyote', 'horse']
>>> df = pd.DataFrame({'speed': speed,
... 'lifespan': lifespan}, index=index)
>>> ax = df.plot.bar(rot=0)
Instead of nesting, the figure can be split by column with
``subplots=True``. In this case, a :class:`numpy.ndarray` of
:class:`matplotlib.axes.Axes` are returned.
.. plot::
:context: close-figs
>>> axes = df.plot.bar(rot=0, subplots=True)
>>> axes[1].legend(loc=2) # doctest: +SKIP
Plot a single column.
.. plot::
:context: close-figs
>>> ax = df.plot.bar(y='speed', rot=0)
Plot only selected categories for the DataFrame.
.. plot::
:context: close-figs
>>> ax = df.plot.bar(x='lifespan', rot=0)
"""
return self(kind='bar', x=x, y=y, **kwds) |
Draw one histogram of the DataFrame's columns.
A histogram is a representation of the distribution of data.
This function groups the values of all given Series in the DataFrame
into bins and draws all bins in one :class:`matplotlib.axes.Axes`.
This is useful when the DataFrame's Series are in a similar scale.
Parameters
----------
by : str or sequence, optional
Column in the DataFrame to group by.
bins : int, default 10
Number of histogram bins to be used.
**kwds
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
class:`matplotlib.AxesSubplot`
Return a histogram plot.
See Also
--------
DataFrame.hist : Draw histograms per DataFrame's Series.
Series.hist : Draw a histogram with Series' data.
Examples
--------
When we draw a dice 6000 times, we expect to get each value around 1000
times. But when we draw two dices and sum the result, the distribution
is going to be quite different. A histogram illustrates those
distributions.
.. plot::
:context: close-figs
>>> df = pd.DataFrame(
... np.random.randint(1, 7, 6000),
... columns = ['one'])
>>> df['two'] = df['one'] + np.random.randint(1, 7, 6000)
>>> ax = df.plot.hist(bins=12, alpha=0.5) | def hist(self, by=None, bins=10, **kwds):
"""
Draw one histogram of the DataFrame's columns.
A histogram is a representation of the distribution of data.
This function groups the values of all given Series in the DataFrame
into bins and draws all bins in one :class:`matplotlib.axes.Axes`.
This is useful when the DataFrame's Series are in a similar scale.
Parameters
----------
by : str or sequence, optional
Column in the DataFrame to group by.
bins : int, default 10
Number of histogram bins to be used.
**kwds
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
class:`matplotlib.AxesSubplot`
Return a histogram plot.
See Also
--------
DataFrame.hist : Draw histograms per DataFrame's Series.
Series.hist : Draw a histogram with Series' data.
Examples
--------
When we draw a dice 6000 times, we expect to get each value around 1000
times. But when we draw two dices and sum the result, the distribution
is going to be quite different. A histogram illustrates those
distributions.
.. plot::
:context: close-figs
>>> df = pd.DataFrame(
... np.random.randint(1, 7, 6000),
... columns = ['one'])
>>> df['two'] = df['one'] + np.random.randint(1, 7, 6000)
>>> ax = df.plot.hist(bins=12, alpha=0.5)
"""
return self(kind='hist', by=by, bins=bins, **kwds) |
Draw a stacked area plot.
An area plot displays quantitative data visually.
This function wraps the matplotlib area function.
Parameters
----------
x : label or position, optional
Coordinates for the X axis. By default uses the index.
y : label or position, optional
Column to plot. By default uses all columns.
stacked : bool, default True
Area plots are stacked by default. Set to False to create a
unstacked plot.
**kwds : optional
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
matplotlib.axes.Axes or numpy.ndarray
Area plot, or array of area plots if subplots is True.
See Also
--------
DataFrame.plot : Make plots of DataFrame using matplotlib / pylab.
Examples
--------
Draw an area plot based on basic business metrics:
.. plot::
:context: close-figs
>>> df = pd.DataFrame({
... 'sales': [3, 2, 3, 9, 10, 6],
... 'signups': [5, 5, 6, 12, 14, 13],
... 'visits': [20, 42, 28, 62, 81, 50],
... }, index=pd.date_range(start='2018/01/01', end='2018/07/01',
... freq='M'))
>>> ax = df.plot.area()
Area plots are stacked by default. To produce an unstacked plot,
pass ``stacked=False``:
.. plot::
:context: close-figs
>>> ax = df.plot.area(stacked=False)
Draw an area plot for a single column:
.. plot::
:context: close-figs
>>> ax = df.plot.area(y='sales')
Draw with a different `x`:
.. plot::
:context: close-figs
>>> df = pd.DataFrame({
... 'sales': [3, 2, 3],
... 'visits': [20, 42, 28],
... 'day': [1, 2, 3],
... })
>>> ax = df.plot.area(x='day') | def area(self, x=None, y=None, **kwds):
"""
Draw a stacked area plot.
An area plot displays quantitative data visually.
This function wraps the matplotlib area function.
Parameters
----------
x : label or position, optional
Coordinates for the X axis. By default uses the index.
y : label or position, optional
Column to plot. By default uses all columns.
stacked : bool, default True
Area plots are stacked by default. Set to False to create a
unstacked plot.
**kwds : optional
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
matplotlib.axes.Axes or numpy.ndarray
Area plot, or array of area plots if subplots is True.
See Also
--------
DataFrame.plot : Make plots of DataFrame using matplotlib / pylab.
Examples
--------
Draw an area plot based on basic business metrics:
.. plot::
:context: close-figs
>>> df = pd.DataFrame({
... 'sales': [3, 2, 3, 9, 10, 6],
... 'signups': [5, 5, 6, 12, 14, 13],
... 'visits': [20, 42, 28, 62, 81, 50],
... }, index=pd.date_range(start='2018/01/01', end='2018/07/01',
... freq='M'))
>>> ax = df.plot.area()
Area plots are stacked by default. To produce an unstacked plot,
pass ``stacked=False``:
.. plot::
:context: close-figs
>>> ax = df.plot.area(stacked=False)
Draw an area plot for a single column:
.. plot::
:context: close-figs
>>> ax = df.plot.area(y='sales')
Draw with a different `x`:
.. plot::
:context: close-figs
>>> df = pd.DataFrame({
... 'sales': [3, 2, 3],
... 'visits': [20, 42, 28],
... 'day': [1, 2, 3],
... })
>>> ax = df.plot.area(x='day')
"""
return self(kind='area', x=x, y=y, **kwds) |
Create a scatter plot with varying marker point size and color.
The coordinates of each point are defined by two dataframe columns and
filled circles are used to represent each point. This kind of plot is
useful to see complex correlations between two variables. Points could
be for instance natural 2D coordinates like longitude and latitude in
a map or, in general, any pair of metrics that can be plotted against
each other.
Parameters
----------
x : int or str
The column name or column position to be used as horizontal
coordinates for each point.
y : int or str
The column name or column position to be used as vertical
coordinates for each point.
s : scalar or array_like, optional
The size of each point. Possible values are:
- A single scalar so all points have the same size.
- A sequence of scalars, which will be used for each point's size
recursively. For instance, when passing [2,14] all points size
will be either 2 or 14, alternatively.
c : str, int or array_like, optional
The color of each point. Possible values are:
- A single color string referred to by name, RGB or RGBA code,
for instance 'red' or '#a98d19'.
- A sequence of color strings referred to by name, RGB or RGBA
code, which will be used for each point's color recursively. For
instance ['green','yellow'] all points will be filled in green or
yellow, alternatively.
- A column name or position whose values will be used to color the
marker points according to a colormap.
**kwds
Keyword arguments to pass on to :meth:`DataFrame.plot`.
Returns
-------
:class:`matplotlib.axes.Axes` or numpy.ndarray of them
See Also
--------
matplotlib.pyplot.scatter : Scatter plot using multiple input data
formats.
Examples
--------
Let's see how to draw a scatter plot using coordinates from the values
in a DataFrame's columns.
.. plot::
:context: close-figs
>>> df = pd.DataFrame([[5.1, 3.5, 0], [4.9, 3.0, 0], [7.0, 3.2, 1],
... [6.4, 3.2, 1], [5.9, 3.0, 2]],
... columns=['length', 'width', 'species'])
>>> ax1 = df.plot.scatter(x='length',
... y='width',
... c='DarkBlue')
And now with the color determined by a column as well.
.. plot::
:context: close-figs
>>> ax2 = df.plot.scatter(x='length',
... y='width',
... c='species',
... colormap='viridis') | def scatter(self, x, y, s=None, c=None, **kwds):
"""
Create a scatter plot with varying marker point size and color.
The coordinates of each point are defined by two dataframe columns and
filled circles are used to represent each point. This kind of plot is
useful to see complex correlations between two variables. Points could
be for instance natural 2D coordinates like longitude and latitude in
a map or, in general, any pair of metrics that can be plotted against
each other.
Parameters
----------
x : int or str
The column name or column position to be used as horizontal
coordinates for each point.
y : int or str
The column name or column position to be used as vertical
coordinates for each point.
s : scalar or array_like, optional
The size of each point. Possible values are:
- A single scalar so all points have the same size.
- A sequence of scalars, which will be used for each point's size
recursively. For instance, when passing [2,14] all points size
will be either 2 or 14, alternatively.
c : str, int or array_like, optional
The color of each point. Possible values are:
- A single color string referred to by name, RGB or RGBA code,
for instance 'red' or '#a98d19'.
- A sequence of color strings referred to by name, RGB or RGBA
code, which will be used for each point's color recursively. For
instance ['green','yellow'] all points will be filled in green or
yellow, alternatively.
- A column name or position whose values will be used to color the
marker points according to a colormap.
**kwds
Keyword arguments to pass on to :meth:`DataFrame.plot`.
Returns
-------
:class:`matplotlib.axes.Axes` or numpy.ndarray of them
See Also
--------
matplotlib.pyplot.scatter : Scatter plot using multiple input data
formats.
Examples
--------
Let's see how to draw a scatter plot using coordinates from the values
in a DataFrame's columns.
.. plot::
:context: close-figs
>>> df = pd.DataFrame([[5.1, 3.5, 0], [4.9, 3.0, 0], [7.0, 3.2, 1],
... [6.4, 3.2, 1], [5.9, 3.0, 2]],
... columns=['length', 'width', 'species'])
>>> ax1 = df.plot.scatter(x='length',
... y='width',
... c='DarkBlue')
And now with the color determined by a column as well.
.. plot::
:context: close-figs
>>> ax2 = df.plot.scatter(x='length',
... y='width',
... c='species',
... colormap='viridis')
"""
return self(kind='scatter', x=x, y=y, c=c, s=s, **kwds) |
Extract combined index: return intersection or union (depending on the
value of "intersect") of indexes on given axis, or None if all objects
lack indexes (e.g. they are numpy arrays).
Parameters
----------
objs : list of objects
Each object will only be considered if it has a _get_axis
attribute.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
axis : {0 or 'index', 1 or 'outer'}, default 0
The axis to extract indexes from.
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index | def _get_objs_combined_axis(objs, intersect=False, axis=0, sort=True):
"""
Extract combined index: return intersection or union (depending on the
value of "intersect") of indexes on given axis, or None if all objects
lack indexes (e.g. they are numpy arrays).
Parameters
----------
objs : list of objects
Each object will only be considered if it has a _get_axis
attribute.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
axis : {0 or 'index', 1 or 'outer'}, default 0
The axis to extract indexes from.
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
obs_idxes = [obj._get_axis(axis) for obj in objs
if hasattr(obj, '_get_axis')]
if obs_idxes:
return _get_combined_index(obs_idxes, intersect=intersect, sort=sort) |
Generate a hexagonal binning plot.
Generate a hexagonal binning plot of `x` versus `y`. If `C` is `None`
(the default), this is a histogram of the number of occurrences
of the observations at ``(x[i], y[i])``.
If `C` is specified, specifies values at given coordinates
``(x[i], y[i])``. These values are accumulated for each hexagonal
bin and then reduced according to `reduce_C_function`,
having as default the NumPy's mean function (:meth:`numpy.mean`).
(If `C` is specified, it must also be a 1-D sequence
of the same length as `x` and `y`, or a column label.)
Parameters
----------
x : int or str
The column label or position for x points.
y : int or str
The column label or position for y points.
C : int or str, optional
The column label or position for the value of `(x, y)` point.
reduce_C_function : callable, default `np.mean`
Function of one argument that reduces all the values in a bin to
a single number (e.g. `np.mean`, `np.max`, `np.sum`, `np.std`).
gridsize : int or tuple of (int, int), default 100
The number of hexagons in the x-direction.
The corresponding number of hexagons in the y-direction is
chosen in a way that the hexagons are approximately regular.
Alternatively, gridsize can be a tuple with two elements
specifying the number of hexagons in the x-direction and the
y-direction.
**kwds
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
matplotlib.AxesSubplot
The matplotlib ``Axes`` on which the hexbin is plotted.
See Also
--------
DataFrame.plot : Make plots of a DataFrame.
matplotlib.pyplot.hexbin : Hexagonal binning plot using matplotlib,
the matplotlib function that is used under the hood.
Examples
--------
The following examples are generated with random data from
a normal distribution.
.. plot::
:context: close-figs
>>> n = 10000
>>> df = pd.DataFrame({'x': np.random.randn(n),
... 'y': np.random.randn(n)})
>>> ax = df.plot.hexbin(x='x', y='y', gridsize=20)
The next example uses `C` and `np.sum` as `reduce_C_function`.
Note that `'observations'` values ranges from 1 to 5 but the result
plot shows values up to more than 25. This is because of the
`reduce_C_function`.
.. plot::
:context: close-figs
>>> n = 500
>>> df = pd.DataFrame({
... 'coord_x': np.random.uniform(-3, 3, size=n),
... 'coord_y': np.random.uniform(30, 50, size=n),
... 'observations': np.random.randint(1,5, size=n)
... })
>>> ax = df.plot.hexbin(x='coord_x',
... y='coord_y',
... C='observations',
... reduce_C_function=np.sum,
... gridsize=10,
... cmap="viridis") | def hexbin(self, x, y, C=None, reduce_C_function=None, gridsize=None,
**kwds):
"""
Generate a hexagonal binning plot.
Generate a hexagonal binning plot of `x` versus `y`. If `C` is `None`
(the default), this is a histogram of the number of occurrences
of the observations at ``(x[i], y[i])``.
If `C` is specified, specifies values at given coordinates
``(x[i], y[i])``. These values are accumulated for each hexagonal
bin and then reduced according to `reduce_C_function`,
having as default the NumPy's mean function (:meth:`numpy.mean`).
(If `C` is specified, it must also be a 1-D sequence
of the same length as `x` and `y`, or a column label.)
Parameters
----------
x : int or str
The column label or position for x points.
y : int or str
The column label or position for y points.
C : int or str, optional
The column label or position for the value of `(x, y)` point.
reduce_C_function : callable, default `np.mean`
Function of one argument that reduces all the values in a bin to
a single number (e.g. `np.mean`, `np.max`, `np.sum`, `np.std`).
gridsize : int or tuple of (int, int), default 100
The number of hexagons in the x-direction.
The corresponding number of hexagons in the y-direction is
chosen in a way that the hexagons are approximately regular.
Alternatively, gridsize can be a tuple with two elements
specifying the number of hexagons in the x-direction and the
y-direction.
**kwds
Additional keyword arguments are documented in
:meth:`DataFrame.plot`.
Returns
-------
matplotlib.AxesSubplot
The matplotlib ``Axes`` on which the hexbin is plotted.
See Also
--------
DataFrame.plot : Make plots of a DataFrame.
matplotlib.pyplot.hexbin : Hexagonal binning plot using matplotlib,
the matplotlib function that is used under the hood.
Examples
--------
The following examples are generated with random data from
a normal distribution.
.. plot::
:context: close-figs
>>> n = 10000
>>> df = pd.DataFrame({'x': np.random.randn(n),
... 'y': np.random.randn(n)})
>>> ax = df.plot.hexbin(x='x', y='y', gridsize=20)
The next example uses `C` and `np.sum` as `reduce_C_function`.
Note that `'observations'` values ranges from 1 to 5 but the result
plot shows values up to more than 25. This is because of the
`reduce_C_function`.
.. plot::
:context: close-figs
>>> n = 500
>>> df = pd.DataFrame({
... 'coord_x': np.random.uniform(-3, 3, size=n),
... 'coord_y': np.random.uniform(30, 50, size=n),
... 'observations': np.random.randint(1,5, size=n)
... })
>>> ax = df.plot.hexbin(x='coord_x',
... y='coord_y',
... C='observations',
... reduce_C_function=np.sum,
... gridsize=10,
... cmap="viridis")
"""
if reduce_C_function is not None:
kwds['reduce_C_function'] = reduce_C_function
if gridsize is not None:
kwds['gridsize'] = gridsize
return self(kind='hexbin', x=x, y=y, C=C, **kwds) |
Return a list with distinct elements of "objs" (different ids).
Preserves order. | def _get_distinct_objs(objs):
"""
Return a list with distinct elements of "objs" (different ids).
Preserves order.
"""
ids = set()
res = []
for obj in objs:
if not id(obj) in ids:
ids.add(id(obj))
res.append(obj)
return res |
Return the union or intersection of indexes.
Parameters
----------
indexes : list of Index or list objects
When intersect=True, do not accept list of lists.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
sort : bool, default False
Whether the result index should come out sorted or not.
Returns
-------
Index | def _get_combined_index(indexes, intersect=False, sort=False):
"""
Return the union or intersection of indexes.
Parameters
----------
indexes : list of Index or list objects
When intersect=True, do not accept list of lists.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
sort : bool, default False
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
# TODO: handle index names!
indexes = _get_distinct_objs(indexes)
if len(indexes) == 0:
index = Index([])
elif len(indexes) == 1:
index = indexes[0]
elif intersect:
index = indexes[0]
for other in indexes[1:]:
index = index.intersection(other)
else:
index = _union_indexes(indexes, sort=sort)
index = ensure_index(index)
if sort:
try:
index = index.sort_values()
except TypeError:
pass
return index |
Return the union of indexes.
The behavior of sort and names is not consistent.
Parameters
----------
indexes : list of Index or list objects
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index | def _union_indexes(indexes, sort=True):
"""
Return the union of indexes.
The behavior of sort and names is not consistent.
Parameters
----------
indexes : list of Index or list objects
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
if len(indexes) == 0:
raise AssertionError('Must have at least 1 Index to union')
if len(indexes) == 1:
result = indexes[0]
if isinstance(result, list):
result = Index(sorted(result))
return result
indexes, kind = _sanitize_and_check(indexes)
def _unique_indices(inds):
"""
Convert indexes to lists and concatenate them, removing duplicates.
The final dtype is inferred.
Parameters
----------
inds : list of Index or list objects
Returns
-------
Index
"""
def conv(i):
if isinstance(i, Index):
i = i.tolist()
return i
return Index(
lib.fast_unique_multiple_list([conv(i) for i in inds], sort=sort))
if kind == 'special':
result = indexes[0]
if hasattr(result, 'union_many'):
return result.union_many(indexes[1:])
else:
for other in indexes[1:]:
result = result.union(other)
return result
elif kind == 'array':
index = indexes[0]
for other in indexes[1:]:
if not index.equals(other):
if sort is None:
# TODO: remove once pd.concat sort default changes
warnings.warn(_sort_msg, FutureWarning, stacklevel=8)
sort = True
return _unique_indices(indexes)
name = _get_consensus_names(indexes)[0]
if name != index.name:
index = index._shallow_copy(name=name)
return index
else: # kind='list'
return _unique_indices(indexes) |
Verify the type of indexes and convert lists to Index.
Cases:
- [list, list, ...]: Return ([list, list, ...], 'list')
- [list, Index, ...]: Return _sanitize_and_check([Index, Index, ...])
Lists are sorted and converted to Index.
- [Index, Index, ...]: Return ([Index, Index, ...], TYPE)
TYPE = 'special' if at least one special type, 'array' otherwise.
Parameters
----------
indexes : list of Index or list objects
Returns
-------
sanitized_indexes : list of Index or list objects
type : {'list', 'array', 'special'} | def _sanitize_and_check(indexes):
"""
Verify the type of indexes and convert lists to Index.
Cases:
- [list, list, ...]: Return ([list, list, ...], 'list')
- [list, Index, ...]: Return _sanitize_and_check([Index, Index, ...])
Lists are sorted and converted to Index.
- [Index, Index, ...]: Return ([Index, Index, ...], TYPE)
TYPE = 'special' if at least one special type, 'array' otherwise.
Parameters
----------
indexes : list of Index or list objects
Returns
-------
sanitized_indexes : list of Index or list objects
type : {'list', 'array', 'special'}
"""
kinds = list({type(index) for index in indexes})
if list in kinds:
if len(kinds) > 1:
indexes = [Index(com.try_sort(x))
if not isinstance(x, Index) else
x for x in indexes]
kinds.remove(list)
else:
return indexes, 'list'
if len(kinds) > 1 or Index not in kinds:
return indexes, 'special'
else:
return indexes, 'array' |
Give a consensus 'names' to indexes.
If there's exactly one non-empty 'names', return this,
otherwise, return empty.
Parameters
----------
indexes : list of Index objects
Returns
-------
list
A list representing the consensus 'names' found. | def _get_consensus_names(indexes):
"""
Give a consensus 'names' to indexes.
If there's exactly one non-empty 'names', return this,
otherwise, return empty.
Parameters
----------
indexes : list of Index objects
Returns
-------
list
A list representing the consensus 'names' found.
"""
# find the non-none names, need to tupleify to make
# the set hashable, then reverse on return
consensus_names = {tuple(i.names) for i in indexes
if com._any_not_none(*i.names)}
if len(consensus_names) == 1:
return list(list(consensus_names)[0])
return [None] * indexes[0].nlevels |
Determine if all indexes contain the same elements.
Parameters
----------
indexes : list of Index objects
Returns
-------
bool
True if all indexes contain the same elements, False otherwise. | def _all_indexes_same(indexes):
"""
Determine if all indexes contain the same elements.
Parameters
----------
indexes : list of Index objects
Returns
-------
bool
True if all indexes contain the same elements, False otherwise.
"""
first = indexes[0]
for index in indexes[1:]:
if not first.equals(index):
return False
return True |
Convert SQL and params args to DBAPI2.0 compliant format. | def _convert_params(sql, params):
"""Convert SQL and params args to DBAPI2.0 compliant format."""
args = [sql]
if params is not None:
if hasattr(params, 'keys'): # test if params is a mapping
args += [params]
else:
args += [list(params)]
return args |
Process parse_dates argument for read_sql functions | def _process_parse_dates_argument(parse_dates):
"""Process parse_dates argument for read_sql functions"""
# handle non-list entries for parse_dates gracefully
if parse_dates is True or parse_dates is None or parse_dates is False:
parse_dates = []
elif not hasattr(parse_dates, '__iter__'):
parse_dates = [parse_dates]
return parse_dates |
Force non-datetime columns to be read as such.
Supports both string formatted and integer timestamp columns. | def _parse_date_columns(data_frame, parse_dates):
"""
Force non-datetime columns to be read as such.
Supports both string formatted and integer timestamp columns.
"""
parse_dates = _process_parse_dates_argument(parse_dates)
# we want to coerce datetime64_tz dtypes for now to UTC
# we could in theory do a 'nice' conversion from a FixedOffset tz
# GH11216
for col_name, df_col in data_frame.iteritems():
if is_datetime64tz_dtype(df_col) or col_name in parse_dates:
try:
fmt = parse_dates[col_name]
except TypeError:
fmt = None
data_frame[col_name] = _handle_date_column(df_col, format=fmt)
return data_frame |
Wrap result set of query in a DataFrame. | def _wrap_result(data, columns, index_col=None, coerce_float=True,
parse_dates=None):
"""Wrap result set of query in a DataFrame."""
frame = DataFrame.from_records(data, columns=columns,
coerce_float=coerce_float)
frame = _parse_date_columns(frame, parse_dates)
if index_col is not None:
frame.set_index(index_col, inplace=True)
return frame |
Execute the given SQL query using the provided connection object.
Parameters
----------
sql : string
SQL query to be executed.
con : SQLAlchemy connectable(engine/connection) or sqlite3 connection
Using SQLAlchemy makes it possible to use any DB supported by the
library.
If a DBAPI2 object, only sqlite3 is supported.
cur : deprecated, cursor is obtained from connection, default: None
params : list or tuple, optional, default: None
List of parameters to pass to execute method.
Returns
-------
Results Iterable | def execute(sql, con, cur=None, params=None):
"""
Execute the given SQL query using the provided connection object.
Parameters
----------
sql : string
SQL query to be executed.
con : SQLAlchemy connectable(engine/connection) or sqlite3 connection
Using SQLAlchemy makes it possible to use any DB supported by the
library.
If a DBAPI2 object, only sqlite3 is supported.
cur : deprecated, cursor is obtained from connection, default: None
params : list or tuple, optional, default: None
List of parameters to pass to execute method.
Returns
-------
Results Iterable
"""
if cur is None:
pandas_sql = pandasSQL_builder(con)
else:
pandas_sql = pandasSQL_builder(cur, is_cursor=True)
args = _convert_params(sql, params)
return pandas_sql.execute(*args) |
Read SQL database table into a DataFrame.
Given a table name and a SQLAlchemy connectable, returns a DataFrame.
This function does not support DBAPI connections.
Parameters
----------
table_name : str
Name of SQL table in database.
con : SQLAlchemy connectable or str
A database URI could be provided as as str.
SQLite DBAPI connection mode not supported.
schema : str, default None
Name of SQL schema in database to query (if database flavor
supports this). Uses default schema if None (default).
index_col : str or list of str, optional, default: None
Column(s) to set as index(MultiIndex).
coerce_float : bool, default True
Attempts to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point. Can result in loss of Precision.
parse_dates : list or dict, default None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict corresponds
to the keyword arguments of :func:`pandas.to_datetime`
Especially useful with databases without native Datetime support,
such as SQLite.
columns : list, default None
List of column names to select from SQL table.
chunksize : int, default None
If specified, returns an iterator where `chunksize` is the number of
rows to include in each chunk.
Returns
-------
DataFrame
A SQL table is returned as two-dimensional data structure with labeled
axes.
See Also
--------
read_sql_query : Read SQL query into a DataFrame.
read_sql : Read SQL query or database table into a DataFrame.
Notes
-----
Any datetime values with time zone information will be converted to UTC.
Examples
--------
>>> pd.read_sql_table('table_name', 'postgres:///db_name') # doctest:+SKIP | def read_sql_table(table_name, con, schema=None, index_col=None,
coerce_float=True, parse_dates=None, columns=None,
chunksize=None):
"""
Read SQL database table into a DataFrame.
Given a table name and a SQLAlchemy connectable, returns a DataFrame.
This function does not support DBAPI connections.
Parameters
----------
table_name : str
Name of SQL table in database.
con : SQLAlchemy connectable or str
A database URI could be provided as as str.
SQLite DBAPI connection mode not supported.
schema : str, default None
Name of SQL schema in database to query (if database flavor
supports this). Uses default schema if None (default).
index_col : str or list of str, optional, default: None
Column(s) to set as index(MultiIndex).
coerce_float : bool, default True
Attempts to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point. Can result in loss of Precision.
parse_dates : list or dict, default None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict corresponds
to the keyword arguments of :func:`pandas.to_datetime`
Especially useful with databases without native Datetime support,
such as SQLite.
columns : list, default None
List of column names to select from SQL table.
chunksize : int, default None
If specified, returns an iterator where `chunksize` is the number of
rows to include in each chunk.
Returns
-------
DataFrame
A SQL table is returned as two-dimensional data structure with labeled
axes.
See Also
--------
read_sql_query : Read SQL query into a DataFrame.
read_sql : Read SQL query or database table into a DataFrame.
Notes
-----
Any datetime values with time zone information will be converted to UTC.
Examples
--------
>>> pd.read_sql_table('table_name', 'postgres:///db_name') # doctest:+SKIP
"""
con = _engine_builder(con)
if not _is_sqlalchemy_connectable(con):
raise NotImplementedError("read_sql_table only supported for "
"SQLAlchemy connectable.")
import sqlalchemy
from sqlalchemy.schema import MetaData
meta = MetaData(con, schema=schema)
try:
meta.reflect(only=[table_name], views=True)
except sqlalchemy.exc.InvalidRequestError:
raise ValueError("Table {name} not found".format(name=table_name))
pandas_sql = SQLDatabase(con, meta=meta)
table = pandas_sql.read_table(
table_name, index_col=index_col, coerce_float=coerce_float,
parse_dates=parse_dates, columns=columns, chunksize=chunksize)
if table is not None:
return table
else:
raise ValueError("Table {name} not found".format(name=table_name), con) |
Read SQL query into a DataFrame.
Returns a DataFrame corresponding to the result set of the query
string. Optionally provide an `index_col` parameter to use one of the
columns as the index, otherwise default integer index will be used.
Parameters
----------
sql : string SQL query or SQLAlchemy Selectable (select or text object)
SQL query to be executed.
con : SQLAlchemy connectable(engine/connection), database string URI,
or sqlite3 DBAPI2 connection
Using SQLAlchemy makes it possible to use any DB supported by that
library.
If a DBAPI2 object, only sqlite3 is supported.
index_col : string or list of strings, optional, default: None
Column(s) to set as index(MultiIndex).
coerce_float : boolean, default True
Attempts to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point. Useful for SQL result sets.
params : list, tuple or dict, optional, default: None
List of parameters to pass to execute method. The syntax used
to pass parameters is database driver dependent. Check your
database driver documentation for which of the five syntax styles,
described in PEP 249's paramstyle, is supported.
Eg. for psycopg2, uses %(name)s so use params={'name' : 'value'}
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict corresponds
to the keyword arguments of :func:`pandas.to_datetime`
Especially useful with databases without native Datetime support,
such as SQLite.
chunksize : int, default None
If specified, return an iterator where `chunksize` is the number of
rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
read_sql
Notes
-----
Any datetime values with time zone information parsed via the `parse_dates`
parameter will be converted to UTC. | def read_sql_query(sql, con, index_col=None, coerce_float=True, params=None,
parse_dates=None, chunksize=None):
"""Read SQL query into a DataFrame.
Returns a DataFrame corresponding to the result set of the query
string. Optionally provide an `index_col` parameter to use one of the
columns as the index, otherwise default integer index will be used.
Parameters
----------
sql : string SQL query or SQLAlchemy Selectable (select or text object)
SQL query to be executed.
con : SQLAlchemy connectable(engine/connection), database string URI,
or sqlite3 DBAPI2 connection
Using SQLAlchemy makes it possible to use any DB supported by that
library.
If a DBAPI2 object, only sqlite3 is supported.
index_col : string or list of strings, optional, default: None
Column(s) to set as index(MultiIndex).
coerce_float : boolean, default True
Attempts to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point. Useful for SQL result sets.
params : list, tuple or dict, optional, default: None
List of parameters to pass to execute method. The syntax used
to pass parameters is database driver dependent. Check your
database driver documentation for which of the five syntax styles,
described in PEP 249's paramstyle, is supported.
Eg. for psycopg2, uses %(name)s so use params={'name' : 'value'}
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict corresponds
to the keyword arguments of :func:`pandas.to_datetime`
Especially useful with databases without native Datetime support,
such as SQLite.
chunksize : int, default None
If specified, return an iterator where `chunksize` is the number of
rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
read_sql
Notes
-----
Any datetime values with time zone information parsed via the `parse_dates`
parameter will be converted to UTC.
"""
pandas_sql = pandasSQL_builder(con)
return pandas_sql.read_query(
sql, index_col=index_col, params=params, coerce_float=coerce_float,
parse_dates=parse_dates, chunksize=chunksize) |
Read SQL query or database table into a DataFrame.
This function is a convenience wrapper around ``read_sql_table`` and
``read_sql_query`` (for backward compatibility). It will delegate
to the specific function depending on the provided input. A SQL query
will be routed to ``read_sql_query``, while a database table name will
be routed to ``read_sql_table``. Note that the delegated function might
have more specific notes about their functionality not listed here.
Parameters
----------
sql : string or SQLAlchemy Selectable (select or text object)
SQL query to be executed or a table name.
con : SQLAlchemy connectable (engine/connection) or database string URI
or DBAPI2 connection (fallback mode)
Using SQLAlchemy makes it possible to use any DB supported by that
library. If a DBAPI2 object, only sqlite3 is supported.
index_col : string or list of strings, optional, default: None
Column(s) to set as index(MultiIndex).
coerce_float : boolean, default True
Attempts to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
params : list, tuple or dict, optional, default: None
List of parameters to pass to execute method. The syntax used
to pass parameters is database driver dependent. Check your
database driver documentation for which of the five syntax styles,
described in PEP 249's paramstyle, is supported.
Eg. for psycopg2, uses %(name)s so use params={'name' : 'value'}
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict corresponds
to the keyword arguments of :func:`pandas.to_datetime`
Especially useful with databases without native Datetime support,
such as SQLite.
columns : list, default: None
List of column names to select from SQL table (only used when reading
a table).
chunksize : int, default None
If specified, return an iterator where `chunksize` is the
number of rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
read_sql_query : Read SQL query into a DataFrame. | def read_sql(sql, con, index_col=None, coerce_float=True, params=None,
parse_dates=None, columns=None, chunksize=None):
"""
Read SQL query or database table into a DataFrame.
This function is a convenience wrapper around ``read_sql_table`` and
``read_sql_query`` (for backward compatibility). It will delegate
to the specific function depending on the provided input. A SQL query
will be routed to ``read_sql_query``, while a database table name will
be routed to ``read_sql_table``. Note that the delegated function might
have more specific notes about their functionality not listed here.
Parameters
----------
sql : string or SQLAlchemy Selectable (select or text object)
SQL query to be executed or a table name.
con : SQLAlchemy connectable (engine/connection) or database string URI
or DBAPI2 connection (fallback mode)
Using SQLAlchemy makes it possible to use any DB supported by that
library. If a DBAPI2 object, only sqlite3 is supported.
index_col : string or list of strings, optional, default: None
Column(s) to set as index(MultiIndex).
coerce_float : boolean, default True
Attempts to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
params : list, tuple or dict, optional, default: None
List of parameters to pass to execute method. The syntax used
to pass parameters is database driver dependent. Check your
database driver documentation for which of the five syntax styles,
described in PEP 249's paramstyle, is supported.
Eg. for psycopg2, uses %(name)s so use params={'name' : 'value'}
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict corresponds
to the keyword arguments of :func:`pandas.to_datetime`
Especially useful with databases without native Datetime support,
such as SQLite.
columns : list, default: None
List of column names to select from SQL table (only used when reading
a table).
chunksize : int, default None
If specified, return an iterator where `chunksize` is the
number of rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
read_sql_query : Read SQL query into a DataFrame.
"""
pandas_sql = pandasSQL_builder(con)
if isinstance(pandas_sql, SQLiteDatabase):
return pandas_sql.read_query(
sql, index_col=index_col, params=params,
coerce_float=coerce_float, parse_dates=parse_dates,
chunksize=chunksize)
try:
_is_table_name = pandas_sql.has_table(sql)
except Exception:
# using generic exception to catch errors from sql drivers (GH24988)
_is_table_name = False
if _is_table_name:
pandas_sql.meta.reflect(only=[sql])
return pandas_sql.read_table(
sql, index_col=index_col, coerce_float=coerce_float,
parse_dates=parse_dates, columns=columns, chunksize=chunksize)
else:
return pandas_sql.read_query(
sql, index_col=index_col, params=params,
coerce_float=coerce_float, parse_dates=parse_dates,
chunksize=chunksize) |
Write records stored in a DataFrame to a SQL database.
Parameters
----------
frame : DataFrame, Series
name : string
Name of SQL table.
con : SQLAlchemy connectable(engine/connection) or database string URI
or sqlite3 DBAPI2 connection
Using SQLAlchemy makes it possible to use any DB supported by that
library.
If a DBAPI2 object, only sqlite3 is supported.
schema : string, default None
Name of SQL schema in database to write to (if database flavor
supports this). If None, use default schema (default).
if_exists : {'fail', 'replace', 'append'}, default 'fail'
- fail: If table exists, do nothing.
- replace: If table exists, drop it, recreate it, and insert data.
- append: If table exists, insert data. Create if does not exist.
index : boolean, default True
Write DataFrame index as a column.
index_label : string or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
chunksize : int, default None
If not None, then rows will be written in batches of this size at a
time. If None, all rows will be written at once.
dtype : single SQLtype or dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a SQLAlchemy type, or a string for sqlite3 fallback connection.
If all columns are of the same type, one single value can be used.
method : {None, 'multi', callable}, default None
Controls the SQL insertion clause used:
- None : Uses standard SQL ``INSERT`` clause (one per row).
- 'multi': Pass multiple values in a single ``INSERT`` clause.
- callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0 | def to_sql(frame, name, con, schema=None, if_exists='fail', index=True,
index_label=None, chunksize=None, dtype=None, method=None):
"""
Write records stored in a DataFrame to a SQL database.
Parameters
----------
frame : DataFrame, Series
name : string
Name of SQL table.
con : SQLAlchemy connectable(engine/connection) or database string URI
or sqlite3 DBAPI2 connection
Using SQLAlchemy makes it possible to use any DB supported by that
library.
If a DBAPI2 object, only sqlite3 is supported.
schema : string, default None
Name of SQL schema in database to write to (if database flavor
supports this). If None, use default schema (default).
if_exists : {'fail', 'replace', 'append'}, default 'fail'
- fail: If table exists, do nothing.
- replace: If table exists, drop it, recreate it, and insert data.
- append: If table exists, insert data. Create if does not exist.
index : boolean, default True
Write DataFrame index as a column.
index_label : string or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
chunksize : int, default None
If not None, then rows will be written in batches of this size at a
time. If None, all rows will be written at once.
dtype : single SQLtype or dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a SQLAlchemy type, or a string for sqlite3 fallback connection.
If all columns are of the same type, one single value can be used.
method : {None, 'multi', callable}, default None
Controls the SQL insertion clause used:
- None : Uses standard SQL ``INSERT`` clause (one per row).
- 'multi': Pass multiple values in a single ``INSERT`` clause.
- callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0
"""
if if_exists not in ('fail', 'replace', 'append'):
raise ValueError("'{0}' is not valid for if_exists".format(if_exists))
pandas_sql = pandasSQL_builder(con, schema=schema)
if isinstance(frame, Series):
frame = frame.to_frame()
elif not isinstance(frame, DataFrame):
raise NotImplementedError("'frame' argument should be either a "
"Series or a DataFrame")
pandas_sql.to_sql(frame, name, if_exists=if_exists, index=index,
index_label=index_label, schema=schema,
chunksize=chunksize, dtype=dtype, method=method) |
Check if DataBase has named table.
Parameters
----------
table_name: string
Name of SQL table.
con: SQLAlchemy connectable(engine/connection) or sqlite3 DBAPI2 connection
Using SQLAlchemy makes it possible to use any DB supported by that
library.
If a DBAPI2 object, only sqlite3 is supported.
schema : string, default None
Name of SQL schema in database to write to (if database flavor supports
this). If None, use default schema (default).
Returns
-------
boolean | def has_table(table_name, con, schema=None):
"""
Check if DataBase has named table.
Parameters
----------
table_name: string
Name of SQL table.
con: SQLAlchemy connectable(engine/connection) or sqlite3 DBAPI2 connection
Using SQLAlchemy makes it possible to use any DB supported by that
library.
If a DBAPI2 object, only sqlite3 is supported.
schema : string, default None
Name of SQL schema in database to write to (if database flavor supports
this). If None, use default schema (default).
Returns
-------
boolean
"""
pandas_sql = pandasSQL_builder(con, schema=schema)
return pandas_sql.has_table(table_name) |
Returns a SQLAlchemy engine from a URI (if con is a string)
else it just return con without modifying it. | def _engine_builder(con):
"""
Returns a SQLAlchemy engine from a URI (if con is a string)
else it just return con without modifying it.
"""
global _SQLALCHEMY_INSTALLED
if isinstance(con, str):
try:
import sqlalchemy
except ImportError:
_SQLALCHEMY_INSTALLED = False
else:
con = sqlalchemy.create_engine(con)
return con
return con |
Convenience function to return the correct PandasSQL subclass based on the
provided parameters. | def pandasSQL_builder(con, schema=None, meta=None,
is_cursor=False):
"""
Convenience function to return the correct PandasSQL subclass based on the
provided parameters.
"""
# When support for DBAPI connections is removed,
# is_cursor should not be necessary.
con = _engine_builder(con)
if _is_sqlalchemy_connectable(con):
return SQLDatabase(con, schema=schema, meta=meta)
elif isinstance(con, str):
raise ImportError("Using URI string without sqlalchemy installed.")
else:
return SQLiteDatabase(con, is_cursor=is_cursor) |
Get the SQL db table schema for the given frame.
Parameters
----------
frame : DataFrame
name : string
name of SQL table
keys : string or sequence, default: None
columns to use a primary key
con: an open SQL database connection object or a SQLAlchemy connectable
Using SQLAlchemy makes it possible to use any DB supported by that
library, default: None
If a DBAPI2 object, only sqlite3 is supported.
dtype : dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a SQLAlchemy type, or a string for sqlite3 fallback connection. | def get_schema(frame, name, keys=None, con=None, dtype=None):
"""
Get the SQL db table schema for the given frame.
Parameters
----------
frame : DataFrame
name : string
name of SQL table
keys : string or sequence, default: None
columns to use a primary key
con: an open SQL database connection object or a SQLAlchemy connectable
Using SQLAlchemy makes it possible to use any DB supported by that
library, default: None
If a DBAPI2 object, only sqlite3 is supported.
dtype : dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a SQLAlchemy type, or a string for sqlite3 fallback connection.
"""
pandas_sql = pandasSQL_builder(con=con)
return pandas_sql._create_sql_schema(frame, name, keys=keys, dtype=dtype) |
Execute SQL statement inserting data
Parameters
----------
conn : sqlalchemy.engine.Engine or sqlalchemy.engine.Connection
keys : list of str
Column names
data_iter : generator of list
Each item contains a list of values to be inserted | def _execute_insert(self, conn, keys, data_iter):
"""Execute SQL statement inserting data
Parameters
----------
conn : sqlalchemy.engine.Engine or sqlalchemy.engine.Connection
keys : list of str
Column names
data_iter : generator of list
Each item contains a list of values to be inserted
"""
data = [dict(zip(keys, row)) for row in data_iter]
conn.execute(self.table.insert(), data) |
Return generator through chunked result set. | def _query_iterator(self, result, chunksize, columns, coerce_float=True,
parse_dates=None):
"""Return generator through chunked result set."""
while True:
data = result.fetchmany(chunksize)
if not data:
break
else:
self.frame = DataFrame.from_records(
data, columns=columns, coerce_float=coerce_float)
self._harmonize_columns(parse_dates=parse_dates)
if self.index is not None:
self.frame.set_index(self.index, inplace=True)
yield self.frame |
Make the DataFrame's column types align with the SQL table
column types.
Need to work around limited NA value support. Floats are always
fine, ints must always be floats if there are Null values.
Booleans are hard because converting bool column with None replaces
all Nones with false. Therefore only convert bool if there are no
NA values.
Datetimes should already be converted to np.datetime64 if supported,
but here we also force conversion if required. | def _harmonize_columns(self, parse_dates=None):
"""
Make the DataFrame's column types align with the SQL table
column types.
Need to work around limited NA value support. Floats are always
fine, ints must always be floats if there are Null values.
Booleans are hard because converting bool column with None replaces
all Nones with false. Therefore only convert bool if there are no
NA values.
Datetimes should already be converted to np.datetime64 if supported,
but here we also force conversion if required.
"""
parse_dates = _process_parse_dates_argument(parse_dates)
for sql_col in self.table.columns:
col_name = sql_col.name
try:
df_col = self.frame[col_name]
# Handle date parsing upfront; don't try to convert columns
# twice
if col_name in parse_dates:
try:
fmt = parse_dates[col_name]
except TypeError:
fmt = None
self.frame[col_name] = _handle_date_column(
df_col, format=fmt)
continue
# the type the dataframe column should have
col_type = self._get_dtype(sql_col.type)
if (col_type is datetime or col_type is date or
col_type is DatetimeTZDtype):
# Convert tz-aware Datetime SQL columns to UTC
utc = col_type is DatetimeTZDtype
self.frame[col_name] = _handle_date_column(df_col, utc=utc)
elif col_type is float:
# floats support NA, can always convert!
self.frame[col_name] = df_col.astype(col_type, copy=False)
elif len(df_col) == df_col.count():
# No NA values, can convert ints and bools
if col_type is np.dtype('int64') or col_type is bool:
self.frame[col_name] = df_col.astype(
col_type, copy=False)
except KeyError:
pass |
Read SQL database table into a DataFrame.
Parameters
----------
table_name : string
Name of SQL table in database.
index_col : string, optional, default: None
Column to set as index.
coerce_float : boolean, default True
Attempts to convert values of non-string, non-numeric objects
(like decimal.Decimal) to floating point. This can result in
loss of precision.
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg}``, where the arg corresponds
to the keyword arguments of :func:`pandas.to_datetime`.
Especially useful with databases without native Datetime support,
such as SQLite.
columns : list, default: None
List of column names to select from SQL table.
schema : string, default None
Name of SQL schema in database to query (if database flavor
supports this). If specified, this overwrites the default
schema of the SQL database object.
chunksize : int, default None
If specified, return an iterator where `chunksize` is the number
of rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
pandas.read_sql_table
SQLDatabase.read_query | def read_table(self, table_name, index_col=None, coerce_float=True,
parse_dates=None, columns=None, schema=None,
chunksize=None):
"""Read SQL database table into a DataFrame.
Parameters
----------
table_name : string
Name of SQL table in database.
index_col : string, optional, default: None
Column to set as index.
coerce_float : boolean, default True
Attempts to convert values of non-string, non-numeric objects
(like decimal.Decimal) to floating point. This can result in
loss of precision.
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg}``, where the arg corresponds
to the keyword arguments of :func:`pandas.to_datetime`.
Especially useful with databases without native Datetime support,
such as SQLite.
columns : list, default: None
List of column names to select from SQL table.
schema : string, default None
Name of SQL schema in database to query (if database flavor
supports this). If specified, this overwrites the default
schema of the SQL database object.
chunksize : int, default None
If specified, return an iterator where `chunksize` is the number
of rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
pandas.read_sql_table
SQLDatabase.read_query
"""
table = SQLTable(table_name, self, index=index_col, schema=schema)
return table.read(coerce_float=coerce_float,
parse_dates=parse_dates, columns=columns,
chunksize=chunksize) |
Return generator through chunked result set | def _query_iterator(result, chunksize, columns, index_col=None,
coerce_float=True, parse_dates=None):
"""Return generator through chunked result set"""
while True:
data = result.fetchmany(chunksize)
if not data:
break
else:
yield _wrap_result(data, columns, index_col=index_col,
coerce_float=coerce_float,
parse_dates=parse_dates) |
Read SQL query into a DataFrame.
Parameters
----------
sql : string
SQL query to be executed.
index_col : string, optional, default: None
Column name to use as index for the returned DataFrame object.
coerce_float : boolean, default True
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
params : list, tuple or dict, optional, default: None
List of parameters to pass to execute method. The syntax used
to pass parameters is database driver dependent. Check your
database driver documentation for which of the five syntax styles,
described in PEP 249's paramstyle, is supported.
Eg. for psycopg2, uses %(name)s so use params={'name' : 'value'}
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict
corresponds to the keyword arguments of
:func:`pandas.to_datetime` Especially useful with databases
without native Datetime support, such as SQLite.
chunksize : int, default None
If specified, return an iterator where `chunksize` is the number
of rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
read_sql | def read_query(self, sql, index_col=None, coerce_float=True,
parse_dates=None, params=None, chunksize=None):
"""Read SQL query into a DataFrame.
Parameters
----------
sql : string
SQL query to be executed.
index_col : string, optional, default: None
Column name to use as index for the returned DataFrame object.
coerce_float : boolean, default True
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
params : list, tuple or dict, optional, default: None
List of parameters to pass to execute method. The syntax used
to pass parameters is database driver dependent. Check your
database driver documentation for which of the five syntax styles,
described in PEP 249's paramstyle, is supported.
Eg. for psycopg2, uses %(name)s so use params={'name' : 'value'}
parse_dates : list or dict, default: None
- List of column names to parse as dates.
- Dict of ``{column_name: format string}`` where format string is
strftime compatible in case of parsing string times, or is one of
(D, s, ns, ms, us) in case of parsing integer timestamps.
- Dict of ``{column_name: arg dict}``, where the arg dict
corresponds to the keyword arguments of
:func:`pandas.to_datetime` Especially useful with databases
without native Datetime support, such as SQLite.
chunksize : int, default None
If specified, return an iterator where `chunksize` is the number
of rows to include in each chunk.
Returns
-------
DataFrame
See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
read_sql
"""
args = _convert_params(sql, params)
result = self.execute(*args)
columns = result.keys()
if chunksize is not None:
return self._query_iterator(result, chunksize, columns,
index_col=index_col,
coerce_float=coerce_float,
parse_dates=parse_dates)
else:
data = result.fetchall()
frame = _wrap_result(data, columns, index_col=index_col,
coerce_float=coerce_float,
parse_dates=parse_dates)
return frame |
Write records stored in a DataFrame to a SQL database.
Parameters
----------
frame : DataFrame
name : string
Name of SQL table.
if_exists : {'fail', 'replace', 'append'}, default 'fail'
- fail: If table exists, do nothing.
- replace: If table exists, drop it, recreate it, and insert data.
- append: If table exists, insert data. Create if does not exist.
index : boolean, default True
Write DataFrame index as a column.
index_label : string or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
schema : string, default None
Name of SQL schema in database to write to (if database flavor
supports this). If specified, this overwrites the default
schema of the SQLDatabase object.
chunksize : int, default None
If not None, then rows will be written in batches of this size at a
time. If None, all rows will be written at once.
dtype : single type or dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a SQLAlchemy type. If all columns are of the same type, one
single value can be used.
method : {None', 'multi', callable}, default None
Controls the SQL insertion clause used:
* None : Uses standard SQL ``INSERT`` clause (one per row).
* 'multi': Pass multiple values in a single ``INSERT`` clause.
* callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0 | def to_sql(self, frame, name, if_exists='fail', index=True,
index_label=None, schema=None, chunksize=None, dtype=None,
method=None):
"""
Write records stored in a DataFrame to a SQL database.
Parameters
----------
frame : DataFrame
name : string
Name of SQL table.
if_exists : {'fail', 'replace', 'append'}, default 'fail'
- fail: If table exists, do nothing.
- replace: If table exists, drop it, recreate it, and insert data.
- append: If table exists, insert data. Create if does not exist.
index : boolean, default True
Write DataFrame index as a column.
index_label : string or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
schema : string, default None
Name of SQL schema in database to write to (if database flavor
supports this). If specified, this overwrites the default
schema of the SQLDatabase object.
chunksize : int, default None
If not None, then rows will be written in batches of this size at a
time. If None, all rows will be written at once.
dtype : single type or dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a SQLAlchemy type. If all columns are of the same type, one
single value can be used.
method : {None', 'multi', callable}, default None
Controls the SQL insertion clause used:
* None : Uses standard SQL ``INSERT`` clause (one per row).
* 'multi': Pass multiple values in a single ``INSERT`` clause.
* callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0
"""
if dtype and not is_dict_like(dtype):
dtype = {col_name: dtype for col_name in frame}
if dtype is not None:
from sqlalchemy.types import to_instance, TypeEngine
for col, my_type in dtype.items():
if not isinstance(to_instance(my_type), TypeEngine):
raise ValueError('The type of {column} is not a '
'SQLAlchemy type '.format(column=col))
table = SQLTable(name, self, frame=frame, index=index,
if_exists=if_exists, index_label=index_label,
schema=schema, dtype=dtype)
table.create()
table.insert(chunksize, method=method)
if (not name.isdigit() and not name.islower()):
# check for potentially case sensitivity issues (GH7815)
# Only check when name is not a number and name is not lower case
engine = self.connectable.engine
with self.connectable.connect() as conn:
table_names = engine.table_names(
schema=schema or self.meta.schema,
connection=conn,
)
if name not in table_names:
msg = (
"The provided table name '{0}' is not found exactly as "
"such in the database after writing the table, possibly "
"due to case sensitivity issues. Consider using lower "
"case table names."
).format(name)
warnings.warn(msg, UserWarning) |
Return a list of SQL statements that creates a table reflecting the
structure of a DataFrame. The first entry will be a CREATE TABLE
statement while the rest will be CREATE INDEX statements. | def _create_table_setup(self):
"""
Return a list of SQL statements that creates a table reflecting the
structure of a DataFrame. The first entry will be a CREATE TABLE
statement while the rest will be CREATE INDEX statements.
"""
column_names_and_types = self._get_column_names_and_types(
self._sql_type_name
)
pat = re.compile(r'\s+')
column_names = [col_name for col_name, _, _ in column_names_and_types]
if any(map(pat.search, column_names)):
warnings.warn(_SAFE_NAMES_WARNING, stacklevel=6)
escape = _get_valid_sqlite_name
create_tbl_stmts = [escape(cname) + ' ' + ctype
for cname, ctype, _ in column_names_and_types]
if self.keys is not None and len(self.keys):
if not is_list_like(self.keys):
keys = [self.keys]
else:
keys = self.keys
cnames_br = ", ".join(escape(c) for c in keys)
create_tbl_stmts.append(
"CONSTRAINT {tbl}_pk PRIMARY KEY ({cnames_br})".format(
tbl=self.name, cnames_br=cnames_br))
create_stmts = ["CREATE TABLE " + escape(self.name) + " (\n" +
',\n '.join(create_tbl_stmts) + "\n)"]
ix_cols = [cname for cname, _, is_index in column_names_and_types
if is_index]
if len(ix_cols):
cnames = "_".join(ix_cols)
cnames_br = ",".join(escape(c) for c in ix_cols)
create_stmts.append(
"CREATE INDEX " + escape("ix_" + self.name + "_" + cnames) +
"ON " + escape(self.name) + " (" + cnames_br + ")")
return create_stmts |
Return generator through chunked result set | def _query_iterator(cursor, chunksize, columns, index_col=None,
coerce_float=True, parse_dates=None):
"""Return generator through chunked result set"""
while True:
data = cursor.fetchmany(chunksize)
if type(data) == tuple:
data = list(data)
if not data:
cursor.close()
break
else:
yield _wrap_result(data, columns, index_col=index_col,
coerce_float=coerce_float,
parse_dates=parse_dates) |
Write records stored in a DataFrame to a SQL database.
Parameters
----------
frame: DataFrame
name: string
Name of SQL table.
if_exists: {'fail', 'replace', 'append'}, default 'fail'
fail: If table exists, do nothing.
replace: If table exists, drop it, recreate it, and insert data.
append: If table exists, insert data. Create if it does not exist.
index : boolean, default True
Write DataFrame index as a column
index_label : string or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
schema : string, default None
Ignored parameter included for compatibility with SQLAlchemy
version of ``to_sql``.
chunksize : int, default None
If not None, then rows will be written in batches of this
size at a time. If None, all rows will be written at once.
dtype : single type or dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a string. If all columns are of the same type, one single value
can be used.
method : {None, 'multi', callable}, default None
Controls the SQL insertion clause used:
* None : Uses standard SQL ``INSERT`` clause (one per row).
* 'multi': Pass multiple values in a single ``INSERT`` clause.
* callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0 | def to_sql(self, frame, name, if_exists='fail', index=True,
index_label=None, schema=None, chunksize=None, dtype=None,
method=None):
"""
Write records stored in a DataFrame to a SQL database.
Parameters
----------
frame: DataFrame
name: string
Name of SQL table.
if_exists: {'fail', 'replace', 'append'}, default 'fail'
fail: If table exists, do nothing.
replace: If table exists, drop it, recreate it, and insert data.
append: If table exists, insert data. Create if it does not exist.
index : boolean, default True
Write DataFrame index as a column
index_label : string or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
schema : string, default None
Ignored parameter included for compatibility with SQLAlchemy
version of ``to_sql``.
chunksize : int, default None
If not None, then rows will be written in batches of this
size at a time. If None, all rows will be written at once.
dtype : single type or dict of column name to SQL type, default None
Optional specifying the datatype for columns. The SQL type should
be a string. If all columns are of the same type, one single value
can be used.
method : {None, 'multi', callable}, default None
Controls the SQL insertion clause used:
* None : Uses standard SQL ``INSERT`` clause (one per row).
* 'multi': Pass multiple values in a single ``INSERT`` clause.
* callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0
"""
if dtype and not is_dict_like(dtype):
dtype = {col_name: dtype for col_name in frame}
if dtype is not None:
for col, my_type in dtype.items():
if not isinstance(my_type, str):
raise ValueError('{column} ({type!s}) not a string'.format(
column=col, type=my_type))
table = SQLiteTable(name, self, frame=frame, index=index,
if_exists=if_exists, index_label=index_label,
dtype=dtype)
table.create()
table.insert(chunksize, method) |
Coerce to a categorical if a series is given.
Internal use ONLY. | def _maybe_to_categorical(array):
"""
Coerce to a categorical if a series is given.
Internal use ONLY.
"""
if isinstance(array, (ABCSeries, ABCCategoricalIndex)):
return array._values
elif isinstance(array, np.ndarray):
return Categorical(array)
return array |
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method. | def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except KeyError:
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc) |
utility routine to turn values into codes given the specified categories | def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
from pandas.core.algorithms import _get_data_algo, _hashtables
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, '_ndarray_values', values)
categories = getattr(categories, '_ndarray_values', categories)
elif (is_extension_array_dtype(categories.dtype) and
is_object_dtype(values)):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
try:
values = (
categories.dtype.construct_array_type()._from_sequence(values)
)
except Exception:
# but that may fail for any reason, so fall back to object
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
(hash_klass, vec_klass), vals = _get_data_algo(values, _hashtables)
(_, _), cats = _get_data_algo(categories, _hashtables)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats) |
Convert a set of codes for to a new set of categories
Parameters
----------
codes : array
old_categories, new_categories : Index
Returns
-------
new_codes : array
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1]) | def _recode_for_categories(codes, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : array
old_categories, new_categories : Index
Returns
-------
new_codes : array
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
from pandas.core.algorithms import take_1d
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(new_categories.get_indexer(old_categories),
new_categories)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes |
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`. | def _factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
from pandas.core.indexes.category import CategoricalIndex
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical(values):
if isinstance(values, (ABCCategoricalIndex, ABCSeries)):
values = values._values
categories = CategoricalIndex(values.categories, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories |
A higher-level wrapper over `_factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `_factorize_from_iterable` for more info. | def _factorize_from_iterables(iterables):
"""
A higher-level wrapper over `_factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `_factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, lzip(*[_factorize_from_iterable(it) for it in iterables])) |
Copy constructor. | def copy(self):
"""
Copy constructor.
"""
return self._constructor(values=self._codes.copy(),
dtype=self.dtype,
fastpath=True) |
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
.. versionadded:: 0.19.0 | def astype(self, dtype, copy=True):
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
.. versionadded:: 0.19.0
"""
if is_categorical_dtype(dtype):
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
return np.array(self, dtype=dtype, copy=copy) |
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical | def _from_inferred_categories(cls, inferred_categories, inferred_codes,
dtype, true_values=None):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (isinstance(dtype, CategoricalDtype) and
dtype.categories is not None)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted,
categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True) |
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array. | def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v |
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c] | def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories,
self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (not fastpath and self.dtype.categories is not None and
len(new_dtype.categories) != len(self.dtype.categories)):
raise ValueError("new categories need to have the same number of "
"items than the old categories!")
self._dtype = new_dtype |
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`. | def _set_dtype(self, dtype):
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories,
dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True) |
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value. | def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat |
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True. | def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
return self.set_ordered(True, inplace=inplace) |
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False. | def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
return self.set_ordered(False, inplace=inplace) |
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes on python3, which does not considers a S1 string equal to a
single char python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories | def set_categories(self, new_categories, ordered=None, rename=False,
inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes on python3, which does not considers a S1 string equal to a
single char python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if (cat.dtype.categories is not None and
len(new_dtype.categories) < len(cat.dtype.categories)):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(cat.codes, cat.categories,
new_dtype.categories)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat |
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0
.. warning::
Currently, Series are considered list like. In a future version
of pandas they'll be considered dict-like.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B] | def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0
.. warning::
Currently, Series are considered list like. In a future version
of pandas they'll be considered dict-like.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
cat = self if inplace else self.copy()
if isinstance(new_categories, ABCSeries):
msg = ("Treating Series 'new_categories' as a list-like and using "
"the values. In a future version, 'rename_categories' will "
"treat Series like a dictionary.\n"
"For dict-like, use 'new_categories.to_dict()'\n"
"For list-like, use 'new_categories.values'.")
warn(msg, FutureWarning, stacklevel=2)
new_categories = list(new_categories)
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item)
for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat |
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories | def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
if set(self.dtype.categories) != set(new_categories):
raise ValueError("items in new_categories are not the same as in "
"old categories")
return self.set_categories(new_categories, ordered=ordered,
inplace=inplace) |
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories | def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
msg = ("new categories must not include old categories: "
"{already_included!s}")
raise ValueError(msg.format(already_included=already_included))
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat |
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories | def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
if not is_list_like(removals):
removals = [removals]
removal_set = set(list(removals))
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories
if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = [x for x in not_included if notna(x)]
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
msg = "removals must all be in old categories: {not_included!s}"
raise ValueError(msg.format(not_included=not_included))
return self.set_categories(new_categories, ordered=self.ordered,
rename=False, inplace=inplace) |
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories | def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(new_categories,
ordered=self.ordered)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat |
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object') | def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(self._codes.copy(),
categories=new_categories,
ordered=self.ordered)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories),
np.nan)
return np.take(new_categories, self._codes) |
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical | def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError("'fill_value={}' is not present "
"in this Categorical's "
"categories".format(fill_value))
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype) |
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes | def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(
deep=deep) |
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts | def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from numpy import bincount
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = bincount(obs, minlength=ncat or None)
else:
count = bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype,
fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype='int64') |
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
numpy.array
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods. | def get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
numpy.array
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if is_datetimelike(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes,
fill_value=np.nan)
return np.array(self) |
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5] | def sort_values(self, inplace=False, ascending=True, na_position='last'):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
if na_position not in ['last', 'first']:
msg = 'invalid na_position: {na_position!r}'
raise ValueError(msg.format(na_position=na_position))
sorted_idx = nargsort(self,
ascending=ascending,
na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(values=self._codes[sorted_idx],
dtype=self.dtype,
fastpath=True) |
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array | def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype('float64')
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values |
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled | def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError("specifying a limit for fillna has not "
"been implemented yet")
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None,
value).astype(self.categories.dtype)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(values_codes != -1)
codes[indexer] = values_codes[values_codes != -1]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError('"value" parameter must be a scalar, dict '
'or Series, but you passed a '
'"{0}"'.format(type(value).__name__))
return self._constructor(codes, dtype=self.dtype, fastpath=True) |
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default None
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 0.23.0
Deprecated the default value of `allow_fill`. The deprecated
default is ``True``. In the future, this will change to
``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``. | def take_nd(self, indexer, allow_fill=None, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default None
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 0.23.0
Deprecated the default value of `allow_fill`. The deprecated
default is ``True``. In the future, this will change to
``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
if allow_fill is None:
if (indexer < 0).any():
warn(_take_msg, FutureWarning, stacklevel=2)
allow_fill = True
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
"'fill_value' ('{}') is not in this Categorical's "
"categories."
)
raise TypeError(msg.format(fill_value))
codes = take(self._codes, indexer, allow_fill=allow_fill,
fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result |
Return a slice of myself.
For internal compatibility with numpy arrays. | def _slice(self, slicer):
"""
Return a slice of myself.
For internal compatibility with numpy arrays.
"""
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim "
"categorical")
slicer = slicer[1]
codes = self._codes[slicer]
return self._constructor(values=codes, dtype=self.dtype, fastpath=True) |
a short repr displaying only max_vals and an optional (but default
footer) | def _tidy_repr(self, max_vals=10, footer=True):
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num):]._get_repr(length=False, footer=False)
result = '{head}, ..., {tail}'.format(head=head[:-1], tail=tail[1:])
if footer:
result = '{result}\n{footer}'.format(
result=result, footer=self._repr_footer())
return str(result) |
return the base repr for the categories | def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (10 if get_option("display.max_categories") == 0 else
get_option("display.max_categories"))
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs |
Returns a string representation of the footer. | def _repr_categories_info(self):
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = getattr(self.categories, 'dtype_str',
str(self.categories.dtype))
levheader = "Categories ({length}, {dtype}): ".format(
length=len(self.categories), dtype=dtype)
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]" |
return an indexer coerced to the codes dtype | def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == 'i':
indexer = indexer.astype(self._codes.dtype)
return indexer |
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Example
-------
In [1]: c = pd.Categorical(list('aabca'))
In [2]: c
Out[2]:
[a, a, b, c, a]
Categories (3, object): [a, b, c]
In [3]: c.categories
Out[3]: Index(['a', 'b', 'c'], dtype='object')
In [4]: c.codes
Out[4]: array([0, 0, 1, 2, 0], dtype=int8)
In [5]: c._reverse_indexer()
Out[5]: {'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])} | def _reverse_indexer(self):
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Example
-------
In [1]: c = pd.Categorical(list('aabca'))
In [2]: c
Out[2]:
[a, a, b, c, a]
Categories (3, object): [a, b, c]
In [3]: c.categories
Out[3]: Index(['a', 'b', 'c'], dtype='object')
In [4]: c.codes
Out[4]: array([0, 0, 1, 2, 0], dtype=int8)
In [5]: c._reverse_indexer()
Out[5]: {'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(self.codes.astype('int64'),
categories.size)
counts = counts.cumsum()
result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, result))
return result |
Subsets and Splits