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projektAI/venv/Lib/site-packages/pandas/core/indexing.py

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2021-06-06 22:13:05 +02:00
from contextlib import suppress
from typing import TYPE_CHECKING, Any, Hashable, List, Sequence, Tuple, Union
import warnings
import numpy as np
from pandas._config.config import option_context
from pandas._libs.indexing import NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError, InvalidIndexError
from pandas.util._decorators import doc
from pandas.core.dtypes.common import (
is_array_like,
is_bool_dtype,
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import infer_fill_value, isna
import pandas.core.common as com
from pandas.core.construction import array as pd_array
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index
if TYPE_CHECKING:
from pandas import DataFrame, Series
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
... index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""
Mixin for adding .loc/.iloc/.at/.iat to Dataframes and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- An alignable boolean Series. The index of the key will be aligned before
masking.
- An alignable Index. The Index of the returned selection will be the input.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`.
Raises
------
KeyError
If any items are not found.
IndexingError
If an indexed key is passed and its index is unalignable to the frame index.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Alignable boolean Series:
>>> df.loc[pd.Series([False, True, False],
... index=['viper', 'sidewinder', 'cobra'])]
max_speed shield
sidewinder 7 8
Index (same behavior as ``df.reindex``)
>>> df.loc[pd.Index(["cobra", "viper"], name="foo")]
max_speed shield
foo
cobra 1 2
viper 4 5
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _LocationIndexer(NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_setitem_indexer(self, key):
"""
Convert a potentially-label-based key into a positional indexer.
"""
if self.name == "loc":
self._ensure_listlike_indexer(key)
if self.axis is not None:
return self._convert_tuple(key, is_setter=True)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
with suppress(TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
return ax.get_loc(key)
if isinstance(key, tuple):
with suppress(IndexingError):
return self._convert_tuple(key, is_setter=True)
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0, is_setter=True)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
elif "unhashable type" in str(e):
raise
raise IndexingError(key) from e
def _ensure_listlike_indexer(self, key, axis=None, value=None):
"""
Ensure that a list-like of column labels are all present by adding them if
they do not already exist.
Parameters
----------
key : list-like of column labels
Target labels.
axis : key axis if known
"""
column_axis = 1
# column only exists in 2-dimensional DataFrame
if self.ndim != 2:
return
if isinstance(key, tuple) and len(key) > 1:
# key may be a tuple if we are .loc
# if length of key is > 1 set key to column part
key = key[column_axis]
axis = column_axis
if (
axis == column_axis
and not isinstance(self.obj.columns, ABCMultiIndex)
and is_list_like_indexer(key)
and not com.is_bool_indexer(key)
and all(is_hashable(k) for k in key)
):
# GH#38148
keys = self.obj.columns.union(key, sort=False)
self.obj._mgr = self.obj._mgr.reindex_axis(
keys, axis=0, copy=False, consolidate=False, only_slice=True
)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._has_valid_setitem_indexer(key)
iloc = self if self.name == "iloc" else self.obj.iloc
iloc._setitem_with_indexer(indexer, value, self.name)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
self._validate_key_length(key)
for i, k in enumerate(key):
try:
self._validate_key(k, i)
except ValueError as err:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
) from err
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key, is_setter: bool = False):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(
self._convert_to_indexer(key, axis=axis, is_setter=is_setter)
)
else:
keyidx.append(slice(None))
else:
self._validate_key_length(key)
for i, k in enumerate(key):
idx = self._convert_to_indexer(k, axis=i, is_setter=is_setter)
keyidx.append(idx)
return tuple(keyidx)
def _validate_key_length(self, key: Sequence[Any]) -> None:
if len(key) > self.ndim:
raise IndexingError("Too many indexers")
def _getitem_tuple_same_dim(self, tup: Tuple):
"""
Index with indexers that should return an object of the same dimension
as self.obj.
This is only called after a failed call to _getitem_lowerdim.
"""
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
# We should never have retval.ndim < self.ndim, as that should
# be handled by the _getitem_lowerdim call above.
assert retval.ndim == self.ndim
return retval
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
with suppress(IndexingError):
return self._handle_lowerdim_multi_index_axis0(tup)
self._validate_key_length(tup)
for i, key in enumerate(tup):
if is_label_like(key):
# We don't need to check for tuples here because those are
# caught by the _is_nested_tuple_indexer check above.
section = self._getitem_axis(key, axis=i)
# We should never have a scalar section here, because
# _getitem_lowerdim is only called after a check for
# is_scalar_access, which that would be.
if section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
# Note: the section.ndim == self.ndim check above
# rules out having DataFrame here, so we dont need to worry
# about transposing.
new_key = tup[:i] + tup[i + 1 :]
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
if self.name != "loc":
# This should never be reached, but lets be explicit about it
raise ValueError("Too many indices")
with suppress(IndexingError):
return self._handle_lowerdim_multi_index_axis0(tup)
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for key in tup:
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
with suppress(KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
return self.obj._get_value(*key, takeable=self._takeable)
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_tuple(self, tup: Tuple):
raise AbstractMethodError(self)
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _has_valid_setitem_indexer(self, indexer) -> bool:
raise AbstractMethodError(self)
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@doc(IndexingMixin.loc)
class _LocIndexer(_LocationIndexer):
_takeable: bool = False
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
# -------------------------------------------------------------------
# Key Checks
@doc(_LocationIndexer._validate_key)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
pass
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
# -------------------------------------------------------------------
# MultiIndex Handling
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, self.obj._AXIS_ORDERS)
}
return self.obj._reindex_with_indexers(d, copy=True, allow_dups=True)
# -------------------------------------------------------------------
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an iterable collection of keys.
Parameters
----------
key : iterable
Targeted labels.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# we assume that not com.is_bool_indexer(key), as that is
# handled before we get here.
self._validate_key(key, axis)
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _getitem_tuple(self, tup: Tuple):
with suppress(IndexingError):
return self._getitem_lowerdim(tup)
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
return self._getitem_tuple_same_dim(tup)
def _get_label(self, label, axis: int):
# GH#5667 this will fail if the label is not present in the axis.
return self.obj.xs(label, axis=axis)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except (TypeError, InvalidIndexError):
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if self.ndim < len(tup) <= self.obj.index.nlevels:
raise ek
raise IndexingError("No label returned")
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = labels._get_partial_string_timestamp_match_key(key)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind="loc"
)
if isinstance(indexer, slice):
return self.obj._slice(indexer, axis=axis)
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="loc")
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except InvalidIndexError:
# GH35015, using datetime as column indices raises exception
if not isinstance(labels, ABCMultiIndex):
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
# always valid
return {"key": key}
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
ax = self.obj._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
indexer, keyarr = ax._convert_listlike_indexer(key)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
# _validate_read_indexer is a no-op if no -1s, so skip
return ax[indexer], indexer
if ax._index_as_unique:
indexer = ax.get_indexer_for(keyarr)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
if len(key) == 0:
return
# Count missing values:
missing_mask = indexer < 0
missing = (missing_mask).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
ax = self.obj._get_axis(axis)
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if raise_missing:
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
not_found = key[missing_mask]
with option_context("display.max_seq_items", 10, "display.width", 80):
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported. "
f"The following labels were missing: {not_found}. "
"See https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
@doc(IndexingMixin.iloc)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
# -------------------------------------------------------------------
# Key Checks
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError("iloc cannot enlarge its target object")
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError("iloc cannot enlarge its target object")
elif isinstance(i, dict):
raise IndexError("iloc cannot enlarge its target object")
return True
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for k in key:
if not is_integer(k):
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
# -------------------------------------------------------------------
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
with suppress(IndexingError):
return self._getitem_lowerdim(tup)
return self._getitem_tuple_same_dim(tup)
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError as err:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds") from err
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self.obj._ixs(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
labels._validate_positional_slice(slice_obj)
return self.obj._slice(slice_obj, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Much simpler as we only have to deal with our valid types.
"""
return key
def _get_setitem_indexer(self, key):
# GH#32257 Fall through to let numpy do validation
return key
# -------------------------------------------------------------------
def _setitem_with_indexer(self, indexer, value, name="iloc"):
"""
_setitem_with_indexer is for setting values on a Series/DataFrame
using positional indexers.
If the relevant keys are not present, the Series/DataFrame may be
expanded.
This method is currently broken when dealing with non-unique Indexes,
since it goes from positional indexers back to labels when calling
BlockManager methods, see GH#12991, GH#22046, GH#15686.
"""
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = not self.obj._mgr.is_single_block
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._mgr.blocks:
if self.ndim > 1:
# in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
blk = self.obj._mgr.blocks[0]
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == info_axis:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
if not len(self.obj):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return
# add a new item with the dtype setup
if com.is_null_slice(indexer[0]):
# We are setting an entire column
self.obj[key] = value
else:
self.obj[key] = infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value, name)
return
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._mgr = self.obj.reindex(labels, axis=i)._mgr
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
self._setitem_with_indexer_missing(indexer, value)
return
# align and set the values
if take_split_path:
# We have to operate column-wise
self._setitem_with_indexer_split_path(indexer, value, name)
else:
self._setitem_single_block(indexer, value, name)
def _setitem_with_indexer_split_path(self, indexer, value, name: str):
"""
Setitem column-wise.
"""
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if len(indexer) > self.ndim:
raise IndexError("too many indices for array")
if isinstance(indexer[0], np.ndarray) and indexer[0].ndim > 2:
raise ValueError(r"Cannot set values with ndim > 2")
if isinstance(value, ABCSeries) and name != "iloc":
value = self._align_series(indexer, value)
# Ensure we have something we can iterate over
info_axis = indexer[1]
ilocs = self._ensure_iterable_column_indexer(info_axis)
pi = indexer[0]
lplane_indexer = length_of_indexer(pi, self.obj.index)
# lplane_indexer gives the expected length of obj[indexer[0]]
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
if isinstance(value, ABCDataFrame):
self._setitem_with_indexer_frame_value(indexer, value, name)
elif np.ndim(value) == 2:
self._setitem_with_indexer_2d_value(indexer, value)
elif len(ilocs) == 1 and lplane_indexer == len(value) and not is_scalar(pi):
# We are setting multiple rows in a single column.
self._setitem_single_column(ilocs[0], value, pi)
elif len(ilocs) == 1 and 0 != lplane_indexer != len(value):
# We are trying to set N values into M entries of a single
# column, which is invalid for N != M
# Exclude zero-len for e.g. boolean masking that is all-false
if len(value) == 1 and not is_integer(info_axis):
# This is a case like df.iloc[:3, [1]] = [0]
# where we treat as df.iloc[:3, 1] = 0
return self._setitem_with_indexer((pi, info_axis[0]), value[0])
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
elif lplane_indexer == 0 and len(value) == len(self.obj.index):
# We get here in one case via .loc with a all-False mask
pass
elif len(ilocs) == len(value):
# We are setting multiple columns in a single row.
for loc, v in zip(ilocs, value):
self._setitem_single_column(loc, v, pi)
elif len(ilocs) == 1 and com.is_null_slice(pi) and len(self.obj) == 0:
# This is a setitem-with-expansion, see
# test_loc_setitem_empty_append_expands_rows_mixed_dtype
# e.g. df = DataFrame(columns=["x", "y"])
# df["x"] = df["x"].astype(np.int64)
# df.loc[:, "x"] = [1, 2, 3]
self._setitem_single_column(ilocs[0], value, pi)
else:
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
else:
# scalar value
for loc in ilocs:
self._setitem_single_column(loc, value, pi)
def _setitem_with_indexer_2d_value(self, indexer, value):
# We get here with np.ndim(value) == 2, excluding DataFrame,
# which goes through _setitem_with_indexer_frame_value
pi = indexer[0]
ilocs = self._ensure_iterable_column_indexer(indexer[1])
# GH#7551 Note that this coerces the dtype if we are mixed
value = np.array(value, dtype=object)
if len(ilocs) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value when setting with an ndarray"
)
for i, loc in enumerate(ilocs):
# setting with a list, re-coerces
self._setitem_single_column(loc, value[:, i].tolist(), pi)
def _setitem_with_indexer_frame_value(self, indexer, value: "DataFrame", name: str):
ilocs = self._ensure_iterable_column_indexer(indexer[1])
sub_indexer = list(indexer)
pi = indexer[0]
multiindex_indexer = isinstance(self.obj.columns, ABCMultiIndex)
unique_cols = value.columns.is_unique
# We do not want to align the value in case of iloc GH#37728
if name == "iloc":
for i, loc in enumerate(ilocs):
val = value.iloc[:, i]
self._setitem_single_column(loc, val, pi)
elif not unique_cols and value.columns.equals(self.obj.columns):
# We assume we are already aligned, see
# test_iloc_setitem_frame_duplicate_columns_multiple_blocks
for loc in ilocs:
item = self.obj.columns[loc]
if item in value:
sub_indexer[1] = item
val = self._align_series(
tuple(sub_indexer),
value.iloc[:, loc],
multiindex_indexer,
)
else:
val = np.nan
self._setitem_single_column(loc, val, pi)
elif not unique_cols:
raise ValueError("Setting with non-unique columns is not allowed.")
else:
for loc in ilocs:
item = self.obj.columns[loc]
if item in value:
sub_indexer[1] = item
val = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
val = np.nan
self._setitem_single_column(loc, val, pi)
def _setitem_single_column(self, loc: int, value, plane_indexer):
"""
Parameters
----------
loc : int
Indexer for column position
plane_indexer : int, slice, listlike[int]
The indexer we use for setitem along axis=0.
"""
pi = plane_indexer
ser = self.obj._ixs(loc, axis=1)
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH#6149 (null slice), GH#10408 (full bounds)
if com.is_null_slice(pi) or com.is_full_slice(pi, len(self.obj)):
ser = value
else:
# set the item, possibly having a dtype change
ser = ser.copy()
ser._mgr = ser._mgr.setitem(indexer=(pi,), value=value)
ser._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj._iset_item(loc, ser)
def _setitem_single_block(self, indexer, value, name: str):
"""
_setitem_with_indexer for the case when we have a single Block.
"""
from pandas import Series
info_axis = self.obj._info_axis_number
item_labels = self.obj._get_axis(info_axis)
if isinstance(indexer, tuple):
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
indexer = maybe_convert_ix(*indexer)
if (isinstance(value, ABCSeries) and name != "iloc") or isinstance(value, dict):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame) and name != "iloc":
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._mgr = self.obj._mgr.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
# We get only here with loc, so can hard code
return self._setitem_with_indexer(new_indexer, value, "loc")
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._mgr = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._mgr
self.obj._maybe_update_cacher(clear=True)
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
elif isinstance(value, dict):
value = Series(
value, index=self.obj.columns, name=indexer, dtype=object
)
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._mgr = self.obj.append(value)._mgr
self.obj._maybe_update_cacher(clear=True)
def _ensure_iterable_column_indexer(self, column_indexer):
"""
Ensure that our column indexer is something that can be iterated over.
"""
if is_integer(column_indexer):
ilocs = [column_indexer]
elif isinstance(column_indexer, slice):
ilocs = np.arange(len(self.obj.columns))[column_indexer]
elif isinstance(column_indexer, np.ndarray) and is_bool_dtype(
column_indexer.dtype
):
ilocs = np.arange(len(column_indexer))[column_indexer]
else:
ilocs = column_indexer
return ilocs
def _align_series(self, indexer, ser: "Series", multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = (indexer,)
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: "DataFrame"):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
class _ScalarAccessIndexer(NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = (key,)
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
key = list(self._convert_key(key, is_setter=True))
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
self.obj._set_value(*key, value=value, takeable=self._takeable)
@doc(IndexingMixin.at)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# GH 26989
# For series, unpacking key needs to result in the label.
# This is already the case for len(key) == 1; e.g. (1,)
if self.ndim == 1 and len(key) > 1:
key = (key,)
# allow arbitrary setting
if is_setter:
return list(key)
return key
@property
def _axes_are_unique(self) -> bool:
# Only relevant for self.ndim == 2
assert self.ndim == 2
return self.obj.index.is_unique and self.obj.columns.is_unique
def __getitem__(self, key):
if self.ndim == 2 and not self._axes_are_unique:
# GH#33041 fall back to .loc
if not isinstance(key, tuple) or not all(is_scalar(x) for x in key):
raise ValueError("Invalid call for scalar access (getting)!")
return self.obj.loc[key]
return super().__getitem__(key)
def __setitem__(self, key, value):
if self.ndim == 2 and not self._axes_are_unique:
# GH#33041 fall back to .loc
if not isinstance(key, tuple) or not all(is_scalar(x) for x in key):
raise ValueError("Invalid call for scalar access (setting)!")
self.obj.loc[key] = value
return
return super().__setitem__(key, value)
@doc(IndexingMixin.iat)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj: "DataFrame", key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj.columns:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
res = idx._get_string_slice(key)
warnings.warn(
"Indexing a DataFrame with a datetimelike index using a single "
"string to slice the rows, like `frame[string]`, is deprecated "
"and will be removed in a future version. Use `frame.loc[string]` "
"instead.",
FutureWarning,
stacklevel=3,
)
return res
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
return result.astype(bool)._values
if is_object_dtype(key):
# key might be object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
elif not is_array_like(result):
# GH 33924
# key may contain nan elements, check_array_indexer needs bool array
result = pd_array(result, dtype=bool)
return check_array_indexer(index, result)
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
return args
return np.ix_(*args)
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for k in tup:
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def non_reducing_slice(slice_):
"""
Ensure that a slice doesn't reduce to a Series or Scalar.
Any user-passed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def maybe_numeric_slice(df, slice_, include_bool: bool = False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
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