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laywerrobot/lib/python3.6/site-packages/pandas/core/ops.py

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2020-08-27 21:55:39 +02:00
"""
Arithmetic operations for PandasObjects
This is not a public API.
"""
# necessary to enforce truediv in Python 2.X
from __future__ import division
import datetime
import operator
import textwrap
import warnings
import numpy as np
import pandas as pd
from pandas._libs import algos as libalgos, ops as libops
from pandas import compat
from pandas.util._decorators import Appender
from pandas.compat import bind_method
import pandas.core.missing as missing
import pandas.core.common as com
from pandas.errors import NullFrequencyError
from pandas.core.dtypes.missing import notna, isna
from pandas.core.dtypes.common import (
needs_i8_conversion,
is_datetimelike_v_numeric,
is_integer_dtype, is_categorical_dtype,
is_object_dtype, is_timedelta64_dtype,
is_datetime64_dtype, is_datetime64tz_dtype,
is_bool_dtype,
is_list_like,
is_scalar,
_ensure_object)
from pandas.core.dtypes.cast import (
maybe_upcast_putmask, find_common_type,
construct_1d_object_array_from_listlike)
from pandas.core.dtypes.generic import (
ABCSeries,
ABCDataFrame, ABCPanel,
ABCIndex,
ABCSparseSeries, ABCSparseArray)
# -----------------------------------------------------------------------------
# Ops Wrapping Utilities
def get_op_result_name(left, right):
"""
Find the appropriate name to pin to an operation result. This result
should always be either an Index or a Series.
Parameters
----------
left : {Series, Index}
right : object
Returns
-------
name : object
Usually a string
"""
# `left` is always a pd.Series when called from within ops
if isinstance(right, (ABCSeries, pd.Index)):
name = _maybe_match_name(left, right)
else:
name = left.name
return name
def _maybe_match_name(a, b):
"""
Try to find a name to attach to the result of an operation between
a and b. If only one of these has a `name` attribute, return that
name. Otherwise return a consensus name if they match of None if
they have different names.
Parameters
----------
a : object
b : object
Returns
-------
name : str or None
See also
--------
pandas.core.common._consensus_name_attr
"""
a_has = hasattr(a, 'name')
b_has = hasattr(b, 'name')
if a_has and b_has:
if a.name == b.name:
return a.name
else:
# TODO: what if they both have np.nan for their names?
return None
elif a_has:
return a.name
elif b_has:
return b.name
return None
# -----------------------------------------------------------------------------
# Reversed Operations not available in the stdlib operator module.
# Defining these instead of using lambdas allows us to reference them by name.
def radd(left, right):
return right + left
def rsub(left, right):
return right - left
def rmul(left, right):
return right * left
def rdiv(left, right):
return right / left
def rtruediv(left, right):
return right / left
def rfloordiv(left, right):
return right // left
def rmod(left, right):
return right % left
def rdivmod(left, right):
return divmod(right, left)
def rpow(left, right):
return right ** left
def rand_(left, right):
return operator.and_(right, left)
def ror_(left, right):
return operator.or_(right, left)
def rxor(left, right):
return operator.xor(right, left)
# -----------------------------------------------------------------------------
def make_invalid_op(name):
"""
Return a binary method that always raises a TypeError.
Parameters
----------
name : str
Returns
-------
invalid_op : function
"""
def invalid_op(self, other=None):
raise TypeError("cannot perform {name} with this index type: "
"{typ}".format(name=name, typ=type(self).__name__))
invalid_op.__name__ = name
return invalid_op
def _gen_eval_kwargs(name):
"""
Find the keyword arguments to pass to numexpr for the given operation.
Parameters
----------
name : str
Returns
-------
eval_kwargs : dict
Examples
--------
>>> _gen_eval_kwargs("__add__")
{}
>>> _gen_eval_kwargs("rtruediv")
{"reversed": True, "truediv": True}
"""
kwargs = {}
# Series and Panel appear to only pass __add__, __radd__, ...
# but DataFrame gets both these dunder names _and_ non-dunder names
# add, radd, ...
name = name.replace('__', '')
if name.startswith('r'):
if name not in ['radd', 'rand', 'ror', 'rxor']:
# Exclude commutative operations
kwargs['reversed'] = True
if name in ['truediv', 'rtruediv']:
kwargs['truediv'] = True
if name in ['ne']:
kwargs['masker'] = True
return kwargs
def _gen_fill_zeros(name):
"""
Find the appropriate fill value to use when filling in undefined values
in the results of the given operation caused by operating on
(generally dividing by) zero.
Parameters
----------
name : str
Returns
-------
fill_value : {None, np.nan, np.inf}
"""
name = name.strip('__')
if 'div' in name:
# truediv, floordiv, div, and reversed variants
fill_value = np.inf
elif 'mod' in name:
# mod, rmod
fill_value = np.nan
else:
fill_value = None
return fill_value
def _get_frame_op_default_axis(name):
"""
Only DataFrame cares about default_axis, specifically:
special methods have default_axis=None and flex methods
have default_axis='columns'.
Parameters
----------
name : str
Returns
-------
default_axis: str or None
"""
if name.replace('__r', '__') in ['__and__', '__or__', '__xor__']:
# bool methods
return 'columns'
elif name.startswith('__'):
# __add__, __mul__, ...
return None
else:
# add, mul, ...
return 'columns'
def _get_opstr(op, cls):
"""
Find the operation string, if any, to pass to numexpr for this
operation.
Parameters
----------
op : binary operator
cls : class
Returns
-------
op_str : string or None
"""
# numexpr is available for non-sparse classes
subtyp = getattr(cls, '_subtyp', '')
use_numexpr = 'sparse' not in subtyp
if not use_numexpr:
# if we're not using numexpr, then don't pass a str_rep
return None
return {operator.add: '+',
radd: '+',
operator.mul: '*',
rmul: '*',
operator.sub: '-',
rsub: '-',
operator.truediv: '/',
rtruediv: '/',
operator.floordiv: '//',
rfloordiv: '//',
operator.mod: None, # TODO: Why None for mod but '%' for rmod?
rmod: '%',
operator.pow: '**',
rpow: '**',
operator.eq: '==',
operator.ne: '!=',
operator.le: '<=',
operator.lt: '<',
operator.ge: '>=',
operator.gt: '>',
operator.and_: '&',
rand_: '&',
operator.or_: '|',
ror_: '|',
operator.xor: '^',
rxor: '^',
divmod: None,
rdivmod: None}[op]
def _get_op_name(op, special):
"""
Find the name to attach to this method according to conventions
for special and non-special methods.
Parameters
----------
op : binary operator
special : bool
Returns
-------
op_name : str
"""
opname = op.__name__.strip('_')
if special:
opname = '__{opname}__'.format(opname=opname)
return opname
# -----------------------------------------------------------------------------
# Docstring Generation and Templates
_add_example_FRAME = """
>>> a = pd.DataFrame([1, 1, 1, np.nan], index=['a', 'b', 'c', 'd'],
... columns=['one'])
>>> a
one
a 1.0
b 1.0
c 1.0
d NaN
>>> b = pd.DataFrame(dict(one=[1, np.nan, 1, np.nan],
... two=[np.nan, 2, np.nan, 2]),
... index=['a', 'b', 'd', 'e'])
>>> b
one two
a 1.0 NaN
b NaN 2.0
d 1.0 NaN
e NaN 2.0
>>> a.add(b, fill_value=0)
one two
a 2.0 NaN
b 1.0 2.0
c 1.0 NaN
d 1.0 NaN
e NaN 2.0
"""
_sub_example_FRAME = """
>>> a = pd.DataFrame([2, 1, 1, np.nan], index=['a', 'b', 'c', 'd'],
... columns=['one'])
>>> a
one
a 2.0
b 1.0
c 1.0
d NaN
>>> b = pd.DataFrame(dict(one=[1, np.nan, 1, np.nan],
... two=[3, 2, np.nan, 2]),
... index=['a', 'b', 'd', 'e'])
>>> b
one two
a 1.0 3.0
b NaN 2.0
d 1.0 NaN
e NaN 2.0
>>> a.sub(b, fill_value=0)
one two
a 1.0 -3.0
b 1.0 -2.0
c 1.0 NaN
d -1.0 NaN
e NaN -2.0
"""
_op_descriptions = {
# Arithmetic Operators
'add': {'op': '+',
'desc': 'Addition',
'reverse': 'radd',
'df_examples': _add_example_FRAME},
'sub': {'op': '-',
'desc': 'Subtraction',
'reverse': 'rsub',
'df_examples': _sub_example_FRAME},
'mul': {'op': '*',
'desc': 'Multiplication',
'reverse': 'rmul',
'df_examples': None},
'mod': {'op': '%',
'desc': 'Modulo',
'reverse': 'rmod',
'df_examples': None},
'pow': {'op': '**',
'desc': 'Exponential power',
'reverse': 'rpow',
'df_examples': None},
'truediv': {'op': '/',
'desc': 'Floating division',
'reverse': 'rtruediv',
'df_examples': None},
'floordiv': {'op': '//',
'desc': 'Integer division',
'reverse': 'rfloordiv',
'df_examples': None},
'divmod': {'op': 'divmod',
'desc': 'Integer division and modulo',
'reverse': None,
'df_examples': None},
# Comparison Operators
'eq': {'op': '==',
'desc': 'Equal to',
'reverse': None,
'df_examples': None},
'ne': {'op': '!=',
'desc': 'Not equal to',
'reverse': None,
'df_examples': None},
'lt': {'op': '<',
'desc': 'Less than',
'reverse': None,
'df_examples': None},
'le': {'op': '<=',
'desc': 'Less than or equal to',
'reverse': None,
'df_examples': None},
'gt': {'op': '>',
'desc': 'Greater than',
'reverse': None,
'df_examples': None},
'ge': {'op': '>=',
'desc': 'Greater than or equal to',
'reverse': None,
'df_examples': None}}
_op_names = list(_op_descriptions.keys())
for key in _op_names:
_op_descriptions[key]['reversed'] = False
reverse_op = _op_descriptions[key]['reverse']
if reverse_op is not None:
_op_descriptions[reverse_op] = _op_descriptions[key].copy()
_op_descriptions[reverse_op]['reversed'] = True
_op_descriptions[reverse_op]['reverse'] = key
_flex_doc_SERIES = """
{desc} of series and other, element-wise (binary operator `{op_name}`).
Equivalent to ``{equiv}``, but with support to substitute a fill_value for
missing data in one of the inputs.
Parameters
----------
other : Series or scalar value
fill_value : None or float value, default None (NaN)
Fill existing missing (NaN) values, and any new element needed for
successful Series alignment, with this value before computation.
If data in both corresponding Series locations is missing
the result will be missing
level : int or name
Broadcast across a level, matching Index values on the
passed MultiIndex level
Returns
-------
result : Series
Examples
--------
>>> a = pd.Series([1, 1, 1, np.nan], index=['a', 'b', 'c', 'd'])
>>> a
a 1.0
b 1.0
c 1.0
d NaN
dtype: float64
>>> b = pd.Series([1, np.nan, 1, np.nan], index=['a', 'b', 'd', 'e'])
>>> b
a 1.0
b NaN
d 1.0
e NaN
dtype: float64
>>> a.add(b, fill_value=0)
a 2.0
b 1.0
c 1.0
d 1.0
e NaN
dtype: float64
See also
--------
Series.{reverse}
"""
_arith_doc_FRAME = """
Binary operator %s with support to substitute a fill_value for missing data in
one of the inputs
Parameters
----------
other : Series, DataFrame, or constant
axis : {0, 1, 'index', 'columns'}
For Series input, axis to match Series index on
fill_value : None or float value, default None
Fill existing missing (NaN) values, and any new element needed for
successful DataFrame alignment, with this value before computation.
If data in both corresponding DataFrame locations is missing
the result will be missing
level : int or name
Broadcast across a level, matching Index values on the
passed MultiIndex level
Notes
-----
Mismatched indices will be unioned together
Returns
-------
result : DataFrame
"""
_flex_doc_FRAME = """
{desc} of dataframe and other, element-wise (binary operator `{op_name}`).
Equivalent to ``{equiv}``, but with support to substitute a fill_value for
missing data in one of the inputs.
Parameters
----------
other : Series, DataFrame, or constant
axis : {{0, 1, 'index', 'columns'}}
For Series input, axis to match Series index on
level : int or name
Broadcast across a level, matching Index values on the
passed MultiIndex level
fill_value : None or float value, default None
Fill existing missing (NaN) values, and any new element needed for
successful DataFrame alignment, with this value before computation.
If data in both corresponding DataFrame locations is missing
the result will be missing
Notes
-----
Mismatched indices will be unioned together
Returns
-------
result : DataFrame
Examples
--------
{df_examples}
See also
--------
DataFrame.{reverse}
"""
_flex_doc_PANEL = """
{desc} of series and other, element-wise (binary operator `{op_name}`).
Equivalent to ``{equiv}``.
Parameters
----------
other : DataFrame or Panel
axis : {{items, major_axis, minor_axis}}
Axis to broadcast over
Returns
-------
Panel
See also
--------
Panel.{reverse}
"""
_agg_doc_PANEL = """
Wrapper method for {op_name}
Parameters
----------
other : DataFrame or Panel
axis : {{items, major_axis, minor_axis}}
Axis to broadcast over
Returns
-------
Panel
"""
def _make_flex_doc(op_name, typ):
"""
Make the appropriate substitutions for the given operation and class-typ
into either _flex_doc_SERIES or _flex_doc_FRAME to return the docstring
to attach to a generated method.
Parameters
----------
op_name : str {'__add__', '__sub__', ... '__eq__', '__ne__', ...}
typ : str {series, 'dataframe']}
Returns
-------
doc : str
"""
op_name = op_name.replace('__', '')
op_desc = _op_descriptions[op_name]
if op_desc['reversed']:
equiv = 'other ' + op_desc['op'] + ' ' + typ
else:
equiv = typ + ' ' + op_desc['op'] + ' other'
if typ == 'series':
base_doc = _flex_doc_SERIES
doc = base_doc.format(desc=op_desc['desc'], op_name=op_name,
equiv=equiv, reverse=op_desc['reverse'])
elif typ == 'dataframe':
base_doc = _flex_doc_FRAME
doc = base_doc.format(desc=op_desc['desc'], op_name=op_name,
equiv=equiv, reverse=op_desc['reverse'],
df_examples=op_desc['df_examples'])
elif typ == 'panel':
base_doc = _flex_doc_PANEL
doc = base_doc.format(desc=op_desc['desc'], op_name=op_name,
equiv=equiv, reverse=op_desc['reverse'])
else:
raise AssertionError('Invalid typ argument.')
return doc
# -----------------------------------------------------------------------------
# Masking NA values and fallbacks for operations numpy does not support
def fill_binop(left, right, fill_value):
"""
If a non-None fill_value is given, replace null entries in left and right
with this value, but only in positions where _one_ of left/right is null,
not both.
Parameters
----------
left : array-like
right : array-like
fill_value : object
Returns
-------
left : array-like
right : array-like
Notes
-----
Makes copies if fill_value is not None
"""
# TODO: can we make a no-copy implementation?
if fill_value is not None:
left_mask = isna(left)
right_mask = isna(right)
left = left.copy()
right = right.copy()
# one but not both
mask = left_mask ^ right_mask
left[left_mask & mask] = fill_value
right[right_mask & mask] = fill_value
return left, right
def mask_cmp_op(x, y, op, allowed_types):
"""
Apply the function `op` to only non-null points in x and y.
Parameters
----------
x : array-like
y : array-like
op : binary operation
allowed_types : class or tuple of classes
Returns
-------
result : ndarray[bool]
"""
# TODO: Can we make the allowed_types arg unnecessary?
xrav = x.ravel()
result = np.empty(x.size, dtype=bool)
if isinstance(y, allowed_types):
yrav = y.ravel()
mask = notna(xrav) & notna(yrav)
result[mask] = op(np.array(list(xrav[mask])),
np.array(list(yrav[mask])))
else:
mask = notna(xrav)
result[mask] = op(np.array(list(xrav[mask])), y)
if op == operator.ne: # pragma: no cover
np.putmask(result, ~mask, True)
else:
np.putmask(result, ~mask, False)
result = result.reshape(x.shape)
return result
# -----------------------------------------------------------------------------
# Functions that add arithmetic methods to objects, given arithmetic factory
# methods
def _get_method_wrappers(cls):
"""
Find the appropriate operation-wrappers to use when defining flex/special
arithmetic, boolean, and comparison operations with the given class.
Parameters
----------
cls : class
Returns
-------
arith_flex : function or None
comp_flex : function or None
arith_special : function
comp_special : function
bool_special : function
Notes
-----
None is only returned for SparseArray
"""
if issubclass(cls, ABCSparseSeries):
# Be sure to catch this before ABCSeries and ABCSparseArray,
# as they will both come see SparseSeries as a subclass
arith_flex = _flex_method_SERIES
comp_flex = _flex_method_SERIES
arith_special = _arith_method_SPARSE_SERIES
comp_special = _arith_method_SPARSE_SERIES
bool_special = _bool_method_SERIES
# TODO: I don't think the functions defined by bool_method are tested
elif issubclass(cls, ABCSeries):
# Just Series; SparseSeries is caught above
arith_flex = _flex_method_SERIES
comp_flex = _flex_method_SERIES
arith_special = _arith_method_SERIES
comp_special = _comp_method_SERIES
bool_special = _bool_method_SERIES
elif issubclass(cls, ABCSparseArray):
arith_flex = None
comp_flex = None
arith_special = _arith_method_SPARSE_ARRAY
comp_special = _arith_method_SPARSE_ARRAY
bool_special = _arith_method_SPARSE_ARRAY
elif issubclass(cls, ABCPanel):
arith_flex = _flex_method_PANEL
comp_flex = _comp_method_PANEL
arith_special = _arith_method_PANEL
comp_special = _comp_method_PANEL
bool_special = _arith_method_PANEL
elif issubclass(cls, ABCDataFrame):
# Same for DataFrame and SparseDataFrame
arith_flex = _arith_method_FRAME
comp_flex = _flex_comp_method_FRAME
arith_special = _arith_method_FRAME
comp_special = _comp_method_FRAME
bool_special = _arith_method_FRAME
return arith_flex, comp_flex, arith_special, comp_special, bool_special
def _create_methods(cls, arith_method, comp_method, bool_method,
special=False):
# creates actual methods based upon arithmetic, comp and bool method
# constructors.
have_divmod = issubclass(cls, ABCSeries)
# divmod is available for Series and SparseSeries
# yapf: disable
new_methods = dict(
add=arith_method(cls, operator.add, special),
radd=arith_method(cls, radd, special),
sub=arith_method(cls, operator.sub, special),
mul=arith_method(cls, operator.mul, special),
truediv=arith_method(cls, operator.truediv, special),
floordiv=arith_method(cls, operator.floordiv, special),
# Causes a floating point exception in the tests when numexpr enabled,
# so for now no speedup
mod=arith_method(cls, operator.mod, special),
pow=arith_method(cls, operator.pow, special),
# not entirely sure why this is necessary, but previously was included
# so it's here to maintain compatibility
rmul=arith_method(cls, rmul, special),
rsub=arith_method(cls, rsub, special),
rtruediv=arith_method(cls, rtruediv, special),
rfloordiv=arith_method(cls, rfloordiv, special),
rpow=arith_method(cls, rpow, special),
rmod=arith_method(cls, rmod, special))
# yapf: enable
new_methods['div'] = new_methods['truediv']
new_methods['rdiv'] = new_methods['rtruediv']
if have_divmod:
# divmod doesn't have an op that is supported by numexpr
new_methods['divmod'] = arith_method(cls, divmod, special)
new_methods.update(dict(
eq=comp_method(cls, operator.eq, special),
ne=comp_method(cls, operator.ne, special),
lt=comp_method(cls, operator.lt, special),
gt=comp_method(cls, operator.gt, special),
le=comp_method(cls, operator.le, special),
ge=comp_method(cls, operator.ge, special)))
if bool_method:
new_methods.update(
dict(and_=bool_method(cls, operator.and_, special),
or_=bool_method(cls, operator.or_, special),
# For some reason ``^`` wasn't used in original.
xor=bool_method(cls, operator.xor, special),
rand_=bool_method(cls, rand_, special),
ror_=bool_method(cls, ror_, special),
rxor=bool_method(cls, rxor, special)))
if special:
dunderize = lambda x: '__{name}__'.format(name=x.strip('_'))
else:
dunderize = lambda x: x
new_methods = {dunderize(k): v for k, v in new_methods.items()}
return new_methods
def add_methods(cls, new_methods):
for name, method in new_methods.items():
# For most methods, if we find that the class already has a method
# of the same name, it is OK to over-write it. The exception is
# inplace methods (__iadd__, __isub__, ...) for SparseArray, which
# retain the np.ndarray versions.
force = not (issubclass(cls, ABCSparseArray) and
name.startswith('__i'))
if force or name not in cls.__dict__:
bind_method(cls, name, method)
# ----------------------------------------------------------------------
# Arithmetic
def add_special_arithmetic_methods(cls):
"""
Adds the full suite of special arithmetic methods (``__add__``,
``__sub__``, etc.) to the class.
Parameters
----------
cls : class
special methods will be defined and pinned to this class
"""
_, _, arith_method, comp_method, bool_method = _get_method_wrappers(cls)
new_methods = _create_methods(cls, arith_method, comp_method, bool_method,
special=True)
# inplace operators (I feel like these should get passed an `inplace=True`
# or just be removed
def _wrap_inplace_method(method):
"""
return an inplace wrapper for this method
"""
def f(self, other):
result = method(self, other)
# this makes sure that we are aligned like the input
# we are updating inplace so we want to ignore is_copy
self._update_inplace(result.reindex_like(self, copy=False)._data,
verify_is_copy=False)
return self
return f
new_methods.update(
dict(__iadd__=_wrap_inplace_method(new_methods["__add__"]),
__isub__=_wrap_inplace_method(new_methods["__sub__"]),
__imul__=_wrap_inplace_method(new_methods["__mul__"]),
__itruediv__=_wrap_inplace_method(new_methods["__truediv__"]),
__ifloordiv__=_wrap_inplace_method(new_methods["__floordiv__"]),
__imod__=_wrap_inplace_method(new_methods["__mod__"]),
__ipow__=_wrap_inplace_method(new_methods["__pow__"])))
if not compat.PY3:
new_methods["__idiv__"] = _wrap_inplace_method(new_methods["__div__"])
new_methods.update(
dict(__iand__=_wrap_inplace_method(new_methods["__and__"]),
__ior__=_wrap_inplace_method(new_methods["__or__"]),
__ixor__=_wrap_inplace_method(new_methods["__xor__"])))
add_methods(cls, new_methods=new_methods)
def add_flex_arithmetic_methods(cls):
"""
Adds the full suite of flex arithmetic methods (``pow``, ``mul``, ``add``)
to the class.
Parameters
----------
cls : class
flex methods will be defined and pinned to this class
"""
flex_arith_method, flex_comp_method, _, _, _ = _get_method_wrappers(cls)
new_methods = _create_methods(cls, flex_arith_method,
flex_comp_method, bool_method=None,
special=False)
new_methods.update(dict(multiply=new_methods['mul'],
subtract=new_methods['sub'],
divide=new_methods['div']))
# opt out of bool flex methods for now
assert not any(kname in new_methods for kname in ('ror_', 'rxor', 'rand_'))
add_methods(cls, new_methods=new_methods)
# -----------------------------------------------------------------------------
# Series
def _align_method_SERIES(left, right, align_asobject=False):
""" align lhs and rhs Series """
# ToDo: Different from _align_method_FRAME, list, tuple and ndarray
# are not coerced here
# because Series has inconsistencies described in #13637
if isinstance(right, ABCSeries):
# avoid repeated alignment
if not left.index.equals(right.index):
if align_asobject:
# to keep original value's dtype for bool ops
left = left.astype(object)
right = right.astype(object)
left, right = left.align(right, copy=False)
return left, right
def _construct_result(left, result, index, name, dtype):
"""
If the raw op result has a non-None name (e.g. it is an Index object) and
the name argument is None, then passing name to the constructor will
not be enough; we still need to override the name attribute.
"""
out = left._constructor(result, index=index, dtype=dtype)
out.name = name
return out
def _construct_divmod_result(left, result, index, name, dtype):
"""divmod returns a tuple of like indexed series instead of a single series.
"""
constructor = left._constructor
return (
constructor(result[0], index=index, name=name, dtype=dtype),
constructor(result[1], index=index, name=name, dtype=dtype),
)
def _arith_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
str_rep = _get_opstr(op, cls)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
fill_zeros = _gen_fill_zeros(op_name)
construct_result = (_construct_divmod_result
if op is divmod else _construct_result)
def na_op(x, y):
import pandas.core.computation.expressions as expressions
try:
result = expressions.evaluate(op, str_rep, x, y, **eval_kwargs)
except TypeError:
if isinstance(y, (np.ndarray, ABCSeries, pd.Index)):
dtype = find_common_type([x.dtype, y.dtype])
result = np.empty(x.size, dtype=dtype)
mask = notna(x) & notna(y)
result[mask] = op(x[mask], com._values_from_object(y[mask]))
else:
assert isinstance(x, np.ndarray)
result = np.empty(len(x), dtype=x.dtype)
mask = notna(x)
result[mask] = op(x[mask], y)
result, changed = maybe_upcast_putmask(result, ~mask, np.nan)
result = missing.fill_zeros(result, x, y, op_name, fill_zeros)
return result
def safe_na_op(lvalues, rvalues):
try:
with np.errstate(all='ignore'):
return na_op(lvalues, rvalues)
except Exception:
if is_object_dtype(lvalues):
return libalgos.arrmap_object(lvalues,
lambda x: op(x, rvalues))
raise
def wrapper(left, right):
if isinstance(right, ABCDataFrame):
return NotImplemented
left, right = _align_method_SERIES(left, right)
res_name = get_op_result_name(left, right)
if is_datetime64_dtype(left) or is_datetime64tz_dtype(left):
result = dispatch_to_index_op(op, left, right, pd.DatetimeIndex)
return construct_result(left, result,
index=left.index, name=res_name,
dtype=result.dtype)
elif is_timedelta64_dtype(left):
result = dispatch_to_index_op(op, left, right, pd.TimedeltaIndex)
return construct_result(left, result,
index=left.index, name=res_name,
dtype=result.dtype)
elif is_categorical_dtype(left):
raise TypeError("{typ} cannot perform the operation "
"{op}".format(typ=type(left).__name__, op=str_rep))
lvalues = left.values
rvalues = right
if isinstance(rvalues, ABCSeries):
rvalues = rvalues.values
result = safe_na_op(lvalues, rvalues)
return construct_result(left, result,
index=left.index, name=res_name, dtype=None)
return wrapper
def dispatch_to_index_op(op, left, right, index_class):
"""
Wrap Series left in the given index_class to delegate the operation op
to the index implementation. DatetimeIndex and TimedeltaIndex perform
type checking, timezone handling, overflow checks, etc.
Parameters
----------
op : binary operator (operator.add, operator.sub, ...)
left : Series
right : object
index_class : DatetimeIndex or TimedeltaIndex
Returns
-------
result : object, usually DatetimeIndex, TimedeltaIndex, or Series
"""
left_idx = index_class(left)
# avoid accidentally allowing integer add/sub. For datetime64[tz] dtypes,
# left_idx may inherit a freq from a cached DatetimeIndex.
# See discussion in GH#19147.
if getattr(left_idx, 'freq', None) is not None:
left_idx = left_idx._shallow_copy(freq=None)
try:
result = op(left_idx, right)
except NullFrequencyError:
# DatetimeIndex and TimedeltaIndex with freq == None raise ValueError
# on add/sub of integers (or int-like). We re-raise as a TypeError.
raise TypeError('incompatible type for a datetime/timedelta '
'operation [{name}]'.format(name=op.__name__))
return result
def _comp_method_OBJECT_ARRAY(op, x, y):
if isinstance(y, list):
y = construct_1d_object_array_from_listlike(y)
if isinstance(y, (np.ndarray, ABCSeries, ABCIndex)):
if not is_object_dtype(y.dtype):
y = y.astype(np.object_)
if isinstance(y, (ABCSeries, ABCIndex)):
y = y.values
result = libops.vec_compare(x, y, op)
else:
result = libops.scalar_compare(x, y, op)
return result
def _comp_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
masker = _gen_eval_kwargs(op_name).get('masker', False)
def na_op(x, y):
# dispatch to the categorical if we have a categorical
# in either operand
if is_categorical_dtype(y) and not is_scalar(y):
# The `not is_scalar(y)` check excludes the string "category"
return op(y, x)
elif is_object_dtype(x.dtype):
result = _comp_method_OBJECT_ARRAY(op, x, y)
elif is_datetimelike_v_numeric(x, y):
raise TypeError("invalid type comparison")
else:
# we want to compare like types
# we only want to convert to integer like if
# we are not NotImplemented, otherwise
# we would allow datetime64 (but viewed as i8) against
# integer comparisons
# we have a datetime/timedelta and may need to convert
assert not needs_i8_conversion(x)
mask = None
if not is_scalar(y) and needs_i8_conversion(y):
mask = isna(x) | isna(y)
y = y.view('i8')
x = x.view('i8')
method = getattr(x, op_name, None)
if method is not None:
with np.errstate(all='ignore'):
result = method(y)
if result is NotImplemented:
raise TypeError("invalid type comparison")
else:
result = op(x, y)
if mask is not None and mask.any():
result[mask] = masker
return result
def wrapper(self, other, axis=None):
# Validate the axis parameter
if axis is not None:
self._get_axis_number(axis)
res_name = get_op_result_name(self, other)
if isinstance(other, ABCDataFrame): # pragma: no cover
# Defer to DataFrame implementation; fail early
return NotImplemented
elif isinstance(other, ABCSeries) and not self._indexed_same(other):
raise ValueError("Can only compare identically-labeled "
"Series objects")
elif is_categorical_dtype(self):
# Dispatch to Categorical implementation; pd.CategoricalIndex
# behavior is non-canonical GH#19513
res_values = dispatch_to_index_op(op, self, other, pd.Categorical)
return self._constructor(res_values, index=self.index,
name=res_name)
if is_datetime64_dtype(self) or is_datetime64tz_dtype(self):
# Dispatch to DatetimeIndex to ensure identical
# Series/Index behavior
if (isinstance(other, datetime.date) and
not isinstance(other, datetime.datetime)):
# https://github.com/pandas-dev/pandas/issues/21152
# Compatibility for difference between Series comparison w/
# datetime and date
msg = (
"Comparing Series of datetimes with 'datetime.date'. "
"Currently, the 'datetime.date' is coerced to a "
"datetime. In the future pandas will not coerce, "
"and {future}. "
"To retain the current behavior, "
"convert the 'datetime.date' to a datetime with "
"'pd.Timestamp'."
)
if op in {operator.lt, operator.le, operator.gt, operator.ge}:
future = "a TypeError will be raised"
else:
future = (
"'the values will not compare equal to the "
"'datetime.date'"
)
msg = '\n'.join(textwrap.wrap(msg.format(future=future)))
warnings.warn(msg, FutureWarning, stacklevel=2)
other = pd.Timestamp(other)
res_values = dispatch_to_index_op(op, self, other,
pd.DatetimeIndex)
return self._constructor(res_values, index=self.index,
name=res_name)
elif is_timedelta64_dtype(self):
res_values = dispatch_to_index_op(op, self, other,
pd.TimedeltaIndex)
return self._constructor(res_values, index=self.index,
name=res_name)
elif isinstance(other, ABCSeries):
# By this point we have checked that self._indexed_same(other)
res_values = na_op(self.values, other.values)
# rename is needed in case res_name is None and res_values.name
# is not.
return self._constructor(res_values, index=self.index,
name=res_name).rename(res_name)
elif isinstance(other, (np.ndarray, pd.Index)):
# do not check length of zerodim array
# as it will broadcast
if other.ndim != 0 and len(self) != len(other):
raise ValueError('Lengths must match to compare')
res_values = na_op(self.values, np.asarray(other))
result = self._constructor(res_values, index=self.index)
# rename is needed in case res_name is None and self.name
# is not.
return result.__finalize__(self).rename(res_name)
elif isinstance(other, pd.Categorical):
# ordering of checks matters; by this point we know
# that not is_categorical_dtype(self)
res_values = op(self.values, other)
return self._constructor(res_values, index=self.index,
name=res_name)
elif is_scalar(other) and isna(other):
# numpy does not like comparisons vs None
if op is operator.ne:
res_values = np.ones(len(self), dtype=bool)
else:
res_values = np.zeros(len(self), dtype=bool)
return self._constructor(res_values, index=self.index,
name=res_name, dtype='bool')
else:
values = self.get_values()
if isinstance(other, list):
other = np.asarray(other)
with np.errstate(all='ignore'):
res = na_op(values, other)
if is_scalar(res):
raise TypeError('Could not compare {typ} type with Series'
.format(typ=type(other)))
# always return a full value series here
res_values = com._values_from_object(res)
return self._constructor(res_values, index=self.index,
name=res_name, dtype='bool')
return wrapper
def _bool_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
def na_op(x, y):
try:
result = op(x, y)
except TypeError:
if isinstance(y, list):
y = construct_1d_object_array_from_listlike(y)
if isinstance(y, (np.ndarray, ABCSeries)):
if (is_bool_dtype(x.dtype) and is_bool_dtype(y.dtype)):
result = op(x, y) # when would this be hit?
else:
x = _ensure_object(x)
y = _ensure_object(y)
result = libops.vec_binop(x, y, op)
else:
# let null fall thru
if not isna(y):
y = bool(y)
try:
result = libops.scalar_binop(x, y, op)
except:
raise TypeError("cannot compare a dtyped [{dtype}] array "
"with a scalar of type [{typ}]"
.format(dtype=x.dtype,
typ=type(y).__name__))
return result
fill_int = lambda x: x.fillna(0)
fill_bool = lambda x: x.fillna(False).astype(bool)
def wrapper(self, other):
is_self_int_dtype = is_integer_dtype(self.dtype)
self, other = _align_method_SERIES(self, other, align_asobject=True)
if isinstance(other, ABCDataFrame):
# Defer to DataFrame implementation; fail early
return NotImplemented
elif isinstance(other, ABCSeries):
name = get_op_result_name(self, other)
is_other_int_dtype = is_integer_dtype(other.dtype)
other = fill_int(other) if is_other_int_dtype else fill_bool(other)
filler = (fill_int if is_self_int_dtype and is_other_int_dtype
else fill_bool)
res_values = na_op(self.values, other.values)
unfilled = self._constructor(res_values,
index=self.index, name=name)
return filler(unfilled)
else:
# scalars, list, tuple, np.array
filler = (fill_int if is_self_int_dtype and
is_integer_dtype(np.asarray(other)) else fill_bool)
res_values = na_op(self.values, other)
unfilled = self._constructor(res_values, index=self.index)
return filler(unfilled).__finalize__(self)
return wrapper
def _flex_method_SERIES(cls, op, special):
name = _get_op_name(op, special)
doc = _make_flex_doc(name, 'series')
@Appender(doc)
def flex_wrapper(self, other, level=None, fill_value=None, axis=0):
# validate axis
if axis is not None:
self._get_axis_number(axis)
if isinstance(other, ABCSeries):
return self._binop(other, op, level=level, fill_value=fill_value)
elif isinstance(other, (np.ndarray, list, tuple)):
if len(other) != len(self):
raise ValueError('Lengths must be equal')
other = self._constructor(other, self.index)
return self._binop(other, op, level=level, fill_value=fill_value)
else:
if fill_value is not None:
self = self.fillna(fill_value)
return self._constructor(op(self, other),
self.index).__finalize__(self)
flex_wrapper.__name__ = name
return flex_wrapper
# -----------------------------------------------------------------------------
# DataFrame
def _combine_series_frame(self, other, func, fill_value=None, axis=None,
level=None, try_cast=True):
"""
Apply binary operator `func` to self, other using alignment and fill
conventions determined by the fill_value, axis, level, and try_cast kwargs.
Parameters
----------
self : DataFrame
other : Series
func : binary operator
fill_value : object, default None
axis : {0, 1, 'columns', 'index', None}, default None
level : int or None, default None
try_cast : bool, default True
Returns
-------
result : DataFrame
"""
if fill_value is not None:
raise NotImplementedError("fill_value {fill} not supported."
.format(fill=fill_value))
if axis is not None:
axis = self._get_axis_number(axis)
if axis == 0:
return self._combine_match_index(other, func, level=level)
else:
return self._combine_match_columns(other, func, level=level,
try_cast=try_cast)
else:
if not len(other):
return self * np.nan
if not len(self):
# Ambiguous case, use _series so works with DataFrame
return self._constructor(data=self._series, index=self.index,
columns=self.columns)
# default axis is columns
return self._combine_match_columns(other, func, level=level,
try_cast=try_cast)
def _align_method_FRAME(left, right, axis):
""" convert rhs to meet lhs dims if input is list, tuple or np.ndarray """
def to_series(right):
msg = ('Unable to coerce to Series, length must be {req_len}: '
'given {given_len}')
if axis is not None and left._get_axis_name(axis) == 'index':
if len(left.index) != len(right):
raise ValueError(msg.format(req_len=len(left.index),
given_len=len(right)))
right = left._constructor_sliced(right, index=left.index)
else:
if len(left.columns) != len(right):
raise ValueError(msg.format(req_len=len(left.columns),
given_len=len(right)))
right = left._constructor_sliced(right, index=left.columns)
return right
if isinstance(right, np.ndarray):
if right.ndim == 1:
right = to_series(right)
elif right.ndim == 2:
if left.shape != right.shape:
raise ValueError("Unable to coerce to DataFrame, shape "
"must be {req_shape}: given {given_shape}"
.format(req_shape=left.shape,
given_shape=right.shape))
right = left._constructor(right, index=left.index,
columns=left.columns)
elif right.ndim > 2:
raise ValueError('Unable to coerce to Series/DataFrame, dim '
'must be <= 2: {dim}'.format(dim=right.shape))
elif (is_list_like(right) and
not isinstance(right, (ABCSeries, ABCDataFrame))):
# GH17901
right = to_series(right)
return right
def _arith_method_FRAME(cls, op, special):
str_rep = _get_opstr(op, cls)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
fill_zeros = _gen_fill_zeros(op_name)
default_axis = _get_frame_op_default_axis(op_name)
def na_op(x, y):
import pandas.core.computation.expressions as expressions
try:
result = expressions.evaluate(op, str_rep, x, y, **eval_kwargs)
except TypeError:
xrav = x.ravel()
if isinstance(y, (np.ndarray, ABCSeries)):
dtype = find_common_type([x.dtype, y.dtype])
result = np.empty(x.size, dtype=dtype)
yrav = y.ravel()
mask = notna(xrav) & notna(yrav)
xrav = xrav[mask]
if yrav.shape != mask.shape:
# FIXME: GH#5284, GH#5035, GH#19448
# Without specifically raising here we get mismatched
# errors in Py3 (TypeError) vs Py2 (ValueError)
raise ValueError('Cannot broadcast operands together.')
yrav = yrav[mask]
if xrav.size:
with np.errstate(all='ignore'):
result[mask] = op(xrav, yrav)
elif isinstance(x, np.ndarray):
# mask is only meaningful for x
result = np.empty(x.size, dtype=x.dtype)
mask = notna(xrav)
xrav = xrav[mask]
if xrav.size:
with np.errstate(all='ignore'):
result[mask] = op(xrav, y)
else:
raise TypeError("cannot perform operation {op} between "
"objects of type {x} and {y}"
.format(op=op_name, x=type(x), y=type(y)))
result, changed = maybe_upcast_putmask(result, ~mask, np.nan)
result = result.reshape(x.shape)
result = missing.fill_zeros(result, x, y, op_name, fill_zeros)
return result
if op_name in _op_descriptions:
# i.e. include "add" but not "__add__"
doc = _make_flex_doc(op_name, 'dataframe')
else:
doc = _arith_doc_FRAME % op_name
@Appender(doc)
def f(self, other, axis=default_axis, level=None, fill_value=None):
other = _align_method_FRAME(self, other, axis)
if isinstance(other, ABCDataFrame): # Another DataFrame
return self._combine_frame(other, na_op, fill_value, level)
elif isinstance(other, ABCSeries):
return _combine_series_frame(self, other, na_op,
fill_value=fill_value, axis=axis,
level=level, try_cast=True)
else:
if fill_value is not None:
self = self.fillna(fill_value)
return self._combine_const(other, na_op, try_cast=True)
f.__name__ = op_name
return f
def _flex_comp_method_FRAME(cls, op, special):
str_rep = _get_opstr(op, cls)
op_name = _get_op_name(op, special)
default_axis = _get_frame_op_default_axis(op_name)
def na_op(x, y):
try:
with np.errstate(invalid='ignore'):
result = op(x, y)
except TypeError:
result = mask_cmp_op(x, y, op, (np.ndarray, ABCSeries))
return result
@Appender('Wrapper for flexible comparison methods {name}'
.format(name=op_name))
def f(self, other, axis=default_axis, level=None):
other = _align_method_FRAME(self, other, axis)
if isinstance(other, ABCDataFrame):
# Another DataFrame
if not self._indexed_same(other):
self, other = self.align(other, 'outer',
level=level, copy=False)
return self._compare_frame(other, na_op, str_rep)
elif isinstance(other, ABCSeries):
return _combine_series_frame(self, other, na_op,
fill_value=None, axis=axis,
level=level, try_cast=False)
else:
return self._combine_const(other, na_op, try_cast=False)
f.__name__ = op_name
return f
def _comp_method_FRAME(cls, func, special):
str_rep = _get_opstr(func, cls)
op_name = _get_op_name(func, special)
@Appender('Wrapper for comparison method {name}'.format(name=op_name))
def f(self, other):
if isinstance(other, ABCDataFrame):
# Another DataFrame
if not self._indexed_same(other):
raise ValueError('Can only compare identically-labeled '
'DataFrame objects')
return self._compare_frame(other, func, str_rep)
elif isinstance(other, ABCSeries):
return _combine_series_frame(self, other, func,
fill_value=None, axis=None,
level=None, try_cast=False)
else:
# straight boolean comparisons we want to allow all columns
# (regardless of dtype to pass thru) See #4537 for discussion.
res = self._combine_const(other, func,
errors='ignore',
try_cast=False)
return res.fillna(True).astype(bool)
f.__name__ = op_name
return f
# -----------------------------------------------------------------------------
# Panel
def _arith_method_PANEL(cls, op, special):
# work only for scalars
op_name = _get_op_name(op, special)
def f(self, other):
if not is_scalar(other):
raise ValueError('Simple arithmetic with {name} can only be '
'done with scalar values'
.format(name=self._constructor.__name__))
return self._combine(other, op)
f.__name__ = op_name
return f
def _comp_method_PANEL(cls, op, special):
str_rep = _get_opstr(op, cls)
op_name = _get_op_name(op, special)
def na_op(x, y):
import pandas.core.computation.expressions as expressions
try:
result = expressions.evaluate(op, str_rep, x, y)
except TypeError:
result = mask_cmp_op(x, y, op, np.ndarray)
return result
@Appender('Wrapper for comparison method {name}'.format(name=op_name))
def f(self, other, axis=None):
# Validate the axis parameter
if axis is not None:
axis = self._get_axis_number(axis)
if isinstance(other, self._constructor):
return self._compare_constructor(other, na_op, try_cast=False)
elif isinstance(other, (self._constructor_sliced, ABCDataFrame,
ABCSeries)):
raise Exception("input needs alignment for this object [{object}]"
.format(object=self._constructor))
else:
return self._combine_const(other, na_op, try_cast=False)
f.__name__ = op_name
return f
def _flex_method_PANEL(cls, op, special):
str_rep = _get_opstr(op, cls)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
fill_zeros = _gen_fill_zeros(op_name)
def na_op(x, y):
import pandas.core.computation.expressions as expressions
try:
result = expressions.evaluate(op, str_rep, x, y,
errors='raise',
**eval_kwargs)
except TypeError:
result = op(x, y)
# handles discrepancy between numpy and numexpr on division/mod
# by 0 though, given that these are generally (always?)
# non-scalars, I'm not sure whether it's worth it at the moment
result = missing.fill_zeros(result, x, y, op_name, fill_zeros)
return result
if op_name in _op_descriptions:
doc = _make_flex_doc(op_name, 'panel')
else:
# doc strings substitors
doc = _agg_doc_PANEL.format(op_name=op_name)
@Appender(doc)
def f(self, other, axis=0):
return self._combine(other, na_op, axis=axis)
f.__name__ = op_name
return f
# -----------------------------------------------------------------------------
# Sparse
def _cast_sparse_series_op(left, right, opname):
"""
For SparseSeries operation, coerce to float64 if the result is expected
to have NaN or inf values
Parameters
----------
left : SparseArray
right : SparseArray
opname : str
Returns
-------
left : SparseArray
right : SparseArray
"""
opname = opname.strip('_')
if is_integer_dtype(left) and is_integer_dtype(right):
# series coerces to float64 if result should have NaN/inf
if opname in ('floordiv', 'mod') and (right.values == 0).any():
left = left.astype(np.float64)
right = right.astype(np.float64)
elif opname in ('rfloordiv', 'rmod') and (left.values == 0).any():
left = left.astype(np.float64)
right = right.astype(np.float64)
return left, right
def _arith_method_SPARSE_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
def wrapper(self, other):
if isinstance(other, ABCDataFrame):
return NotImplemented
elif isinstance(other, ABCSeries):
if not isinstance(other, ABCSparseSeries):
other = other.to_sparse(fill_value=self.fill_value)
return _sparse_series_op(self, other, op, op_name)
elif is_scalar(other):
with np.errstate(all='ignore'):
new_values = op(self.values, other)
return self._constructor(new_values,
index=self.index,
name=self.name)
else: # pragma: no cover
raise TypeError('operation with {other} not supported'
.format(other=type(other)))
wrapper.__name__ = op_name
return wrapper
def _sparse_series_op(left, right, op, name):
left, right = left.align(right, join='outer', copy=False)
new_index = left.index
new_name = get_op_result_name(left, right)
from pandas.core.sparse.array import _sparse_array_op
lvalues, rvalues = _cast_sparse_series_op(left.values, right.values, name)
result = _sparse_array_op(lvalues, rvalues, op, name)
return left._constructor(result, index=new_index, name=new_name)
def _arith_method_SPARSE_ARRAY(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
def wrapper(self, other):
from pandas.core.sparse.array import (
SparseArray, _sparse_array_op, _wrap_result, _get_fill)
if isinstance(other, np.ndarray):
if len(self) != len(other):
raise AssertionError("length mismatch: {self} vs. {other}"
.format(self=len(self), other=len(other)))
if not isinstance(other, SparseArray):
dtype = getattr(other, 'dtype', None)
other = SparseArray(other, fill_value=self.fill_value,
dtype=dtype)
return _sparse_array_op(self, other, op, op_name)
elif is_scalar(other):
with np.errstate(all='ignore'):
fill = op(_get_fill(self), np.asarray(other))
result = op(self.sp_values, other)
return _wrap_result(op_name, result, self.sp_index, fill)
else: # pragma: no cover
raise TypeError('operation with {other} not supported'
.format(other=type(other)))
wrapper.__name__ = op_name
return wrapper
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