def take(self,
indices: Sequence[int],
allow_fill: bool = False,
fill_value: Any = None) -> "TensorArray":
"""
See docstring in :class:`ExtensionArray` class in ``pandas/core/arrays/base.py``
for information about this method.
"""
if allow_fill:
# From API docs: "[If allow_fill == True, then] negative values in
# `indices` indicate missing values and are set to `fill_value`
indices = np.asarray(indices, dtype=np.intp)
validate_indices(indices, len(self._tensor))
# Check if there are missing indices to fill, if not can use numpy take below
has_missing = np.any(indices < 0)
if has_missing:
if fill_value is None:
fill_value = np.nan
# Create an array populated with fill value
values = np.full((len(indices), ) + self._tensor.shape[1:],
fill_value)
# Iterate over each index and set non-missing elements
for i, idx in enumerate(indices):
if idx >= 0:
values[i] = self._tensor[idx]
return TensorArray(values)
# Delegate take to numpy array
values = self._tensor.take(indices, axis=0)
return TensorArray(values)
def take(self,
indices: Sequence[int],
allow_fill: bool = False,
fill_value: Any = None) -> "TensorArray":
"""
Take elements from an array.
Parameters
----------
indices : sequence of int
Indices to be taken.
allow_fill : bool, default False
How to handle negative values in `indices`.
* False: negative values in `indices` indicate positional indices
from the right (the default). This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate
missing values. These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
fill_value : any, optional
Fill value to use for NA-indices when `allow_fill` is True.
This may be ``None``, in which case the default NA value for
the type, ``self.dtype.na_value``, is used.
For many ExtensionArrays, there will be two representations of
`fill_value`: a user-facing "boxed" scalar, and a low-level
physical NA value. `fill_value` should be the user-facing version,
and the implementation should handle translating that to the
physical version for processing the take if necessary.
Returns
-------
ExtensionArray
Raises
------
IndexError
When the indices are out of bounds for the array.
ValueError
When `indices` contains negative values other than ``-1``
and `allow_fill` is True.
See Also
--------
numpy.take : Take elements from an array along an axis.
api.extensions.take : Take elements from an array.
Notes
-----
ExtensionArray.take is called by ``Series.__getitem__``, ``.loc``,
``iloc``, when `indices` is a sequence of values. Additionally,
it's called by :meth:`Series.reindex`, or any other method
that causes realignment, with a `fill_value`.
Examples
--------
Here's an example implementation, which relies on casting the
extension array to object dtype. This uses the helper method
:func:`pandas.api.extensions.take`.
.. code-block:: python
def take(self, indices, allow_fill=False, fill_value=None):
from pandas.core.algorithms import take
# If the ExtensionArray is backed by an ndarray, then
# just pass that here instead of coercing to object.
data = self.astype(object)
if allow_fill and fill_value is None:
fill_value = self.dtype.na_value
# fill value should always be translated from the scalar
# type for the array, to the physical storage type for
# the data, before passing to take.
result = take(data, indices, fill_value=fill_value,
allow_fill=allow_fill)
return self._from_sequence(result, dtype=self.dtype)
"""
if allow_fill:
# With allow_fill being True, negative values in `indices` indicate
# missing values and should be set to `fill_value`.
indices = np.asarray(indices, dtype=np.intp)
validate_indices(indices, len(self._tensor))
# Check if there are missing indices to fill, otherwise we can
# delegate to NumPy ndarray .take().
has_missing = np.any(indices < 0)
if has_missing:
if fill_value is None:
fill_value = np.nan
# Create an array populated with fill value.
values = np.full((len(indices), ) + self._tensor.shape[1:],
fill_value)
# Put tensors at the given positive indices into array.
is_nonneg = indices >= 0
np.put(values,
np.where(is_nonneg)[0],
self._tensor[indices[is_nonneg]])
return TensorArray(values)
# Delegate take to NumPy array.
values = self._tensor.take(indices, axis=0)
return TensorArray(values)
def _reindex_indexer(
self: T,
new_axis,
indexer,
axis: int,
fill_value=None,
allow_dups: bool = False,
copy: bool = True,
use_na_proxy: bool = False,
) -> T:
"""
Parameters
----------
new_axis : Index
indexer : ndarray of int64 or None
axis : int
fill_value : object, default None
allow_dups : bool, default False
copy : bool, default True
pandas-indexer with -1's only.
"""
if indexer is None:
if new_axis is self._axes[axis] and not copy:
return self
result = self.copy(deep=copy)
result._axes = list(self._axes)
result._axes[axis] = new_axis
return result
# some axes don't allow reindexing with dups
if not allow_dups:
self._axes[axis]._validate_can_reindex(indexer)
if axis >= self.ndim:
raise IndexError("Requested axis not found in manager")
if axis == 1:
new_arrays = []
for i in indexer:
if i == -1:
arr = self._make_na_array(fill_value=fill_value,
use_na_proxy=use_na_proxy)
else:
arr = self.arrays[i]
new_arrays.append(arr)
else:
validate_indices(indexer, len(self._axes[0]))
indexer = ensure_platform_int(indexer)
if (indexer == -1).any():
allow_fill = True
else:
allow_fill = False
new_arrays = [
take_1d(
arr,
indexer,
allow_fill=allow_fill,
fill_value=fill_value,
# if fill_value is not None else blk.fill_value
) for arr in self.arrays
]
new_axes = list(self._axes)
new_axes[axis] = new_axis
return type(self)(new_arrays, new_axes, verify_integrity=False)
def take(self,
indices: Sequence[int],
allow_fill: bool = False,
fill_value: Any = None):
"""
Take elements from an array.
Parameters
----------
indices : sequence of int
Indices to be taken.
allow_fill : bool, default False
How to handle negative values in `indices`.
* False: negative values in `indices` indicate positional indices
from the right (the default). This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate
missing values. These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
fill_value : any, optional
Fill value to use for NA-indices when `allow_fill` is True.
This may be ``None``, in which case the default NA value for
the type, ``self.dtype.na_value``, is used.
For many ExtensionArrays, there will be two representations of
`fill_value`: a user-facing "boxed" scalar, and a low-level
physical NA value. `fill_value` should be the user-facing version,
and the implementation should handle translating that to the
physical version for processing the take if necessary.
Returns
-------
ExtensionArray
Raises
------
IndexError
When the indices are out of bounds for the array.
ValueError
When `indices` contains negative values other than ``-1``
and `allow_fill` is True.
See Also
--------
numpy.take
api.extensions.take
Notes
-----
ExtensionArray.take is called by ``Series.__getitem__``, ``.loc``,
``iloc``, when `indices` is a sequence of values. Additionally,
it's called by :meth:`Series.reindex`, or any other method
that causes realignment, with a `fill_value`.
"""
# TODO: Remove once we got rid of the (indices < 0) check
if not is_array_like(indices):
indices_array = np.asanyarray(indices)
else:
# error: Incompatible types in assignment (expression has type
# "Sequence[int]", variable has type "ndarray")
indices_array = indices # type: ignore[assignment]
if len(self._data) == 0 and (indices_array >= 0).any():
raise IndexError("cannot do a non-empty take")
if indices_array.size > 0 and indices_array.max() >= len(self._data):
raise IndexError("out of bounds value in 'indices'.")
if allow_fill:
fill_mask = indices_array < 0
if fill_mask.any():
validate_indices(indices_array, len(self._data))
# TODO(ARROW-9433): Treat negative indices as NULL
indices_array = pa.array(indices_array, mask=fill_mask)
result = self._data.take(indices_array)
if isna(fill_value):
return type(self)(result)
# TODO: ArrowNotImplementedError: Function fill_null has no
# kernel matching input types (array[string], scalar[string])
result = type(self)(result)
result[fill_mask] = fill_value
return result
# return type(self)(pc.fill_null(result, pa.scalar(fill_value)))
else:
# Nothing to fill
return type(self)(self._data.take(indices))
else: # allow_fill=False
# TODO(ARROW-9432): Treat negative indices as indices from the right.
if (indices_array < 0).any():
# Don't modify in-place
indices_array = np.copy(indices_array)
indices_array[indices_array < 0] += len(self._data)
return type(self)(self._data.take(indices_array))
def test_validate_indices_empty():
with pytest.raises(IndexError, match="indices are out"):
validate_indices(np.array([0, 1]), 0)
def test_validate_indices_high():
indices = np.asarray([0, 1, 2])
with pytest.raises(IndexError, match="indices are out"):
validate_indices(indices, 2)
def test_validate_indices_low():
indices = np.asarray([0, -2])
with pytest.raises(ValueError, match="'indices' contains"):
validate_indices(indices, 2)
def test_validate_indices_ok():
indices = np.asarray([0, 1])
validate_indices(indices, 2)
validate_indices(indices[:0], 0)
validate_indices(np.array([-1, -1]), 0)
def _reindex_indexer(
self: T,
new_axis,
indexer,
axis: int,
fill_value=None,
allow_dups: bool = False,
copy: bool = True,
) -> T:
"""
Parameters
----------
new_axis : Index
indexer : ndarray of int64 or None
axis : int
fill_value : object, default None
allow_dups : bool, default False
copy : bool, default True
pandas-indexer with -1's only.
"""
if indexer is None:
if new_axis is self._axes[axis] and not copy:
return self
result = self.copy(deep=copy)
result._axes = list(self._axes)
result._axes[axis] = new_axis
return result
# some axes don't allow reindexing with dups
if not allow_dups:
self._axes[axis]._validate_can_reindex(indexer)
if axis >= self.ndim:
raise IndexError("Requested axis not found in manager")
if axis == 1:
new_arrays = []
for i in indexer:
if i == -1:
arr = self._make_na_array(fill_value=fill_value)
else:
arr = self.arrays[i]
new_arrays.append(arr)
else:
validate_indices(indexer, len(self._axes[0]))
new_arrays = [
# error: Value of type variable "ArrayLike" of "take_1d" cannot be
# "Union[ndarray, ExtensionArray]" [type-var]
take_1d( # type: ignore[type-var]
arr,
indexer,
allow_fill=True,
fill_value=fill_value,
# if fill_value is not None else blk.fill_value
) for arr in self.arrays
]
new_axes = list(self._axes)
new_axes[axis] = new_axis
return type(self)(new_arrays, new_axes, verify_integrity=False)
def take(self, indices, allow_fill=False, fill_value=None):
# type: (Sequence[int] , bool, Optional[Any]) -> FletcherArray
"""
Take elements from an array.
Parameters
----------
indices : sequence of integers
Indices to be taken.
allow_fill : bool, default False
How to handle negative values in `indices`.
* False: negative values in `indices` indicate positional indices
from the right (the default). This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate
missing values. These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
fill_value : any, optional
Fill value to use for NA-indices when `allow_fill` is True.
This may be ``None``, in which case the default NA value for
the type, ``self.dtype.na_value``, is used.
For many FletcherArrays, there will be two representations of
`fill_value`: a user-facing "boxed" scalar, and a low-level
physical NA value. `fill_value` should be the user-facing version,
and the implementation should handle translating that to the
physical version for processing the take if nescessary.
Returns
-------
FletcherArray
Raises
------
IndexError
When the indices are out of bounds for the array.
ValueError
When `indices` contains negative values other than ``-1``
and `allow_fill` is True.
Notes
-----
ExtensionArray.take is called by ``Series.__getitem__``, ``.loc``,
``iloc``, when `indices` is a sequence of values. Additionally,
it's called by :meth:`Series.reindex`, or any other method
that causes realignemnt, with a `fill_value`.
Notes
-----
FletcherArray.take is called by ``Series.__getitem__``, ``.loc``,
``iloc``, when `indices` is a sequence of values. Additionally,
it's called by :meth:`Series.reindex`, or any other method
that causes realignemnt, with a `fill_value`.
See Also
--------
numpy.take
pandas.api.extensions.take
"""
threshold_ratio = 0.3
# this is the threshold to decide whether or not to concat everything first.
# Benchmarks were made on string, int32, int64, float32, float64 and it turns out that 0.3 is the value where it
# is best to switch to concatening everything first, both time-wise and memory-wise
length = len(self)
indices = np.asarray(indices, dtype=self._indices_dtype)
has_negative_indices = np.any(indices < 0) # type: ignore
allow_fill &= has_negative_indices
if allow_fill:
validate_indices(indices, length)
if (has_negative_indices
and not allow_fill) or np.any(indices >= length # type: ignore
):
# this will raise IndexError expected by pandas in all needed cases
indices = np.arange(length,
dtype=self._indices_dtype).take(indices)
# here we guarantee that indices is numpy array of ints
# and we have checked that all indices are between -1/0 and len(self)
if not allow_fill:
if self._has_single_chunk:
if (self.dtype.is_list
and self.data.chunk(0).flatten().null_count == 0
and self.data.chunk(0).null_count == 0
and self.flatten().dtype._is_numeric):
return FletcherArray(
take_indices_on_pyarrow_list(self.data.chunk(0),
indices))
else:
return FletcherArray(
self.data.chunk(0).take(pa.array(indices)))
lengths = np.fromiter(map(len, self.data.iterchunks()),
dtype=np.int)
cum_lengths = lengths.cumsum()
bins = self._get_chunk_indexer(indices)
cum_lengths -= lengths
limits_idx = np.concatenate(
[[0],
np.bincount(bins, minlength=self.data.num_chunks).cumsum()])
if pd.Series(bins).is_monotonic:
del bins
return self._take_on_chunks(indices,
limits_idx=limits_idx,
cum_lengths=cum_lengths)
elif len(indices) / len(self) > threshold_ratio:
# check which method is going to take less memory
return self._take_on_concatenated_chunks(indices)
else:
sort_idx = get_group_index_sorter(bins, self.data.num_chunks)
del bins
indices = indices.take(sort_idx, out=indices) # type: ignore
sort_idx = np.argsort(sort_idx,
kind="merge") # inverse sort indices
return self._take_on_chunks(
indices,
sort_idx=sort_idx,
limits_idx=limits_idx,
cum_lengths=cum_lengths,
)
else:
if pd.isnull(fill_value):
fill_value = None
return self._concat_same_type(
[self, FletcherArray([fill_value],
dtype=self.data.type)]).take(indices)
