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

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2021-06-06 22:13:05 +02:00
"""
Methods that can be shared by many array-like classes or subclasses:
Series
Index
ExtensionArray
"""
import operator
from typing import Any, Callable
import warnings
import numpy as np
from pandas._libs import lib
from pandas.core.construction import extract_array
from pandas.core.ops import maybe_dispatch_ufunc_to_dunder_op, roperator
from pandas.core.ops.common import unpack_zerodim_and_defer
class OpsMixin:
# -------------------------------------------------------------
# Comparisons
def _cmp_method(self, other, op):
return NotImplemented
@unpack_zerodim_and_defer("__eq__")
def __eq__(self, other):
return self._cmp_method(other, operator.eq)
@unpack_zerodim_and_defer("__ne__")
def __ne__(self, other):
return self._cmp_method(other, operator.ne)
@unpack_zerodim_and_defer("__lt__")
def __lt__(self, other):
return self._cmp_method(other, operator.lt)
@unpack_zerodim_and_defer("__le__")
def __le__(self, other):
return self._cmp_method(other, operator.le)
@unpack_zerodim_and_defer("__gt__")
def __gt__(self, other):
return self._cmp_method(other, operator.gt)
@unpack_zerodim_and_defer("__ge__")
def __ge__(self, other):
return self._cmp_method(other, operator.ge)
# -------------------------------------------------------------
# Logical Methods
def _logical_method(self, other, op):
return NotImplemented
@unpack_zerodim_and_defer("__and__")
def __and__(self, other):
return self._logical_method(other, operator.and_)
@unpack_zerodim_and_defer("__rand__")
def __rand__(self, other):
return self._logical_method(other, roperator.rand_)
@unpack_zerodim_and_defer("__or__")
def __or__(self, other):
return self._logical_method(other, operator.or_)
@unpack_zerodim_and_defer("__ror__")
def __ror__(self, other):
return self._logical_method(other, roperator.ror_)
@unpack_zerodim_and_defer("__xor__")
def __xor__(self, other):
return self._logical_method(other, operator.xor)
@unpack_zerodim_and_defer("__rxor__")
def __rxor__(self, other):
return self._logical_method(other, roperator.rxor)
# -------------------------------------------------------------
# Arithmetic Methods
def _arith_method(self, other, op):
return NotImplemented
@unpack_zerodim_and_defer("__add__")
def __add__(self, other):
return self._arith_method(other, operator.add)
@unpack_zerodim_and_defer("__radd__")
def __radd__(self, other):
return self._arith_method(other, roperator.radd)
@unpack_zerodim_and_defer("__sub__")
def __sub__(self, other):
return self._arith_method(other, operator.sub)
@unpack_zerodim_and_defer("__rsub__")
def __rsub__(self, other):
return self._arith_method(other, roperator.rsub)
@unpack_zerodim_and_defer("__mul__")
def __mul__(self, other):
return self._arith_method(other, operator.mul)
@unpack_zerodim_and_defer("__rmul__")
def __rmul__(self, other):
return self._arith_method(other, roperator.rmul)
@unpack_zerodim_and_defer("__truediv__")
def __truediv__(self, other):
return self._arith_method(other, operator.truediv)
@unpack_zerodim_and_defer("__rtruediv__")
def __rtruediv__(self, other):
return self._arith_method(other, roperator.rtruediv)
@unpack_zerodim_and_defer("__floordiv__")
def __floordiv__(self, other):
return self._arith_method(other, operator.floordiv)
@unpack_zerodim_and_defer("__rfloordiv")
def __rfloordiv__(self, other):
return self._arith_method(other, roperator.rfloordiv)
@unpack_zerodim_and_defer("__mod__")
def __mod__(self, other):
return self._arith_method(other, operator.mod)
@unpack_zerodim_and_defer("__rmod__")
def __rmod__(self, other):
return self._arith_method(other, roperator.rmod)
@unpack_zerodim_and_defer("__divmod__")
def __divmod__(self, other):
return self._arith_method(other, divmod)
@unpack_zerodim_and_defer("__rdivmod__")
def __rdivmod__(self, other):
return self._arith_method(other, roperator.rdivmod)
@unpack_zerodim_and_defer("__pow__")
def __pow__(self, other):
return self._arith_method(other, operator.pow)
@unpack_zerodim_and_defer("__rpow__")
def __rpow__(self, other):
return self._arith_method(other, roperator.rpow)
# -----------------------------------------------------------------------------
# Helpers to implement __array_ufunc__
def _is_aligned(frame, other):
"""
Helper to check if a DataFrame is aligned with another DataFrame or Series.
"""
from pandas import DataFrame
if isinstance(other, DataFrame):
return frame._indexed_same(other)
else:
# Series -> match index
return frame.columns.equals(other.index)
def _maybe_fallback(ufunc: Callable, method: str, *inputs: Any, **kwargs: Any):
"""
In the future DataFrame, inputs to ufuncs will be aligned before applying
the ufunc, but for now we ignore the index but raise a warning if behaviour
would change in the future.
This helper detects the case where a warning is needed and then fallbacks
to applying the ufunc on arrays to avoid alignment.
See https://github.com/pandas-dev/pandas/pull/39239
"""
from pandas import DataFrame
from pandas.core.generic import NDFrame
n_alignable = sum(isinstance(x, NDFrame) for x in inputs)
n_frames = sum(isinstance(x, DataFrame) for x in inputs)
if n_alignable >= 2 and n_frames >= 1:
# if there are 2 alignable inputs (Series or DataFrame), of which at least 1
# is a DataFrame -> we would have had no alignment before -> warn that this
# will align in the future
# the first frame is what determines the output index/columns in pandas < 1.2
first_frame = next(x for x in inputs if isinstance(x, DataFrame))
# check if the objects are aligned or not
non_aligned = sum(
not _is_aligned(first_frame, x) for x in inputs if isinstance(x, NDFrame)
)
# if at least one is not aligned -> warn and fallback to array behaviour
if non_aligned:
warnings.warn(
"Calling a ufunc on non-aligned DataFrames (or DataFrame/Series "
"combination). Currently, the indices are ignored and the result "
"takes the index/columns of the first DataFrame. In the future , "
"the DataFrames/Series will be aligned before applying the ufunc.\n"
"Convert one of the arguments to a NumPy array "
"(eg 'ufunc(df1, np.asarray(df2)') to keep the current behaviour, "
"or align manually (eg 'df1, df2 = df1.align(df2)') before passing to "
"the ufunc to obtain the future behaviour and silence this warning.",
FutureWarning,
stacklevel=4,
)
# keep the first dataframe of the inputs, other DataFrame/Series is
# converted to array for fallback behaviour
new_inputs = []
for x in inputs:
if x is first_frame:
new_inputs.append(x)
elif isinstance(x, NDFrame):
new_inputs.append(np.asarray(x))
else:
new_inputs.append(x)
# call the ufunc on those transformed inputs
return getattr(ufunc, method)(*new_inputs, **kwargs)
# signal that we didn't fallback / execute the ufunc yet
return NotImplemented
def array_ufunc(self, ufunc: Callable, method: str, *inputs: Any, **kwargs: Any):
"""
Compatibility with numpy ufuncs.
See also
--------
numpy.org/doc/stable/reference/arrays.classes.html#numpy.class.__array_ufunc__
"""
from pandas.core.generic import NDFrame
from pandas.core.internals import BlockManager
cls = type(self)
# for backwards compatibility check and potentially fallback for non-aligned frames
result = _maybe_fallback(ufunc, method, *inputs, **kwargs)
if result is not NotImplemented:
return result
# for binary ops, use our custom dunder methods
result = maybe_dispatch_ufunc_to_dunder_op(self, ufunc, method, *inputs, **kwargs)
if result is not NotImplemented:
return result
# Determine if we should defer.
no_defer = (np.ndarray.__array_ufunc__, cls.__array_ufunc__)
for item in inputs:
higher_priority = (
hasattr(item, "__array_priority__")
and item.__array_priority__ > self.__array_priority__
)
has_array_ufunc = (
hasattr(item, "__array_ufunc__")
and type(item).__array_ufunc__ not in no_defer
and not isinstance(item, self._HANDLED_TYPES)
)
if higher_priority or has_array_ufunc:
return NotImplemented
# align all the inputs.
types = tuple(type(x) for x in inputs)
alignable = [x for x, t in zip(inputs, types) if issubclass(t, NDFrame)]
if len(alignable) > 1:
# This triggers alignment.
# At the moment, there aren't any ufuncs with more than two inputs
# so this ends up just being x1.index | x2.index, but we write
# it to handle *args.
if len(set(types)) > 1:
# We currently don't handle ufunc(DataFrame, Series)
# well. Previously this raised an internal ValueError. We might
# support it someday, so raise a NotImplementedError.
raise NotImplementedError(
"Cannot apply ufunc {} to mixed DataFrame and Series "
"inputs.".format(ufunc)
)
axes = self.axes
for obj in alignable[1:]:
# this relies on the fact that we aren't handling mixed
# series / frame ufuncs.
for i, (ax1, ax2) in enumerate(zip(axes, obj.axes)):
axes[i] = ax1.union(ax2)
reconstruct_axes = dict(zip(self._AXIS_ORDERS, axes))
inputs = tuple(
x.reindex(**reconstruct_axes) if issubclass(t, NDFrame) else x
for x, t in zip(inputs, types)
)
else:
reconstruct_axes = dict(zip(self._AXIS_ORDERS, self.axes))
if self.ndim == 1:
names = [getattr(x, "name") for x in inputs if hasattr(x, "name")]
name = names[0] if len(set(names)) == 1 else None
reconstruct_kwargs = {"name": name}
else:
reconstruct_kwargs = {}
def reconstruct(result):
if lib.is_scalar(result):
return result
if result.ndim != self.ndim:
if method == "outer":
if self.ndim == 2:
# we already deprecated for Series
msg = (
"outer method for ufunc {} is not implemented on "
"pandas objects. Returning an ndarray, but in the "
"future this will raise a 'NotImplementedError'. "
"Consider explicitly converting the DataFrame "
"to an array with '.to_numpy()' first."
)
warnings.warn(msg.format(ufunc), FutureWarning, stacklevel=4)
return result
raise NotImplementedError
return result
if isinstance(result, BlockManager):
# we went through BlockManager.apply
result = self._constructor(result, **reconstruct_kwargs, copy=False)
else:
# we converted an array, lost our axes
result = self._constructor(
result, **reconstruct_axes, **reconstruct_kwargs, copy=False
)
# TODO: When we support multiple values in __finalize__, this
# should pass alignable to `__fianlize__` instead of self.
# Then `np.add(a, b)` would consider attrs from both a and b
# when a and b are NDFrames.
if len(alignable) == 1:
result = result.__finalize__(self)
return result
if self.ndim > 1 and (
len(inputs) > 1 or ufunc.nout > 1 # type: ignore[attr-defined]
):
# Just give up on preserving types in the complex case.
# In theory we could preserve them for them.
# * nout>1 is doable if BlockManager.apply took nout and
# returned a Tuple[BlockManager].
# * len(inputs) > 1 is doable when we know that we have
# aligned blocks / dtypes.
inputs = tuple(np.asarray(x) for x in inputs)
result = getattr(ufunc, method)(*inputs, **kwargs)
elif self.ndim == 1:
# ufunc(series, ...)
inputs = tuple(extract_array(x, extract_numpy=True) for x in inputs)
result = getattr(ufunc, method)(*inputs, **kwargs)
else:
# ufunc(dataframe)
if method == "__call__" and not kwargs:
# for np.<ufunc>(..) calls
# kwargs cannot necessarily be handled block-by-block, so only
# take this path if there are no kwargs
mgr = inputs[0]._mgr
result = mgr.apply(getattr(ufunc, method))
else:
# otherwise specific ufunc methods (eg np.<ufunc>.accumulate(..))
# Those can have an axis keyword and thus can't be called block-by-block
result = getattr(ufunc, method)(np.asarray(inputs[0]), **kwargs)
if ufunc.nout > 1: # type: ignore[attr-defined]
result = tuple(reconstruct(x) for x in result)
else:
result = reconstruct(result)
return result