laywerrobot/lib/python3.6/site-packages/pandas/util/_validators.py
2020-08-27 21:55:39 +02:00

358 lines
13 KiB
Python

"""
Module that contains many useful utilities
for validating data or function arguments
"""
import warnings
from pandas.core.dtypes.common import is_bool
def _check_arg_length(fname, args, max_fname_arg_count, compat_args):
"""
Checks whether 'args' has length of at most 'compat_args'. Raises
a TypeError if that is not the case, similar to in Python when a
function is called with too many arguments.
"""
if max_fname_arg_count < 0:
raise ValueError("'max_fname_arg_count' must be non-negative")
if len(args) > len(compat_args):
max_arg_count = len(compat_args) + max_fname_arg_count
actual_arg_count = len(args) + max_fname_arg_count
argument = 'argument' if max_arg_count == 1 else 'arguments'
raise TypeError(
"{fname}() takes at most {max_arg} {argument} "
"({given_arg} given)".format(
fname=fname, max_arg=max_arg_count,
argument=argument, given_arg=actual_arg_count))
def _check_for_default_values(fname, arg_val_dict, compat_args):
"""
Check that the keys in `arg_val_dict` are mapped to their
default values as specified in `compat_args`.
Note that this function is to be called only when it has been
checked that arg_val_dict.keys() is a subset of compat_args
"""
for key in arg_val_dict:
# try checking equality directly with '=' operator,
# as comparison may have been overridden for the left
# hand object
try:
v1 = arg_val_dict[key]
v2 = compat_args[key]
# check for None-ness otherwise we could end up
# comparing a numpy array vs None
if (v1 is not None and v2 is None) or \
(v1 is None and v2 is not None):
match = False
else:
match = (v1 == v2)
if not is_bool(match):
raise ValueError("'match' is not a boolean")
# could not compare them directly, so try comparison
# using the 'is' operator
except:
match = (arg_val_dict[key] is compat_args[key])
if not match:
raise ValueError(("the '{arg}' parameter is not "
"supported in the pandas "
"implementation of {fname}()".
format(fname=fname, arg=key)))
def validate_args(fname, args, max_fname_arg_count, compat_args):
"""
Checks whether the length of the `*args` argument passed into a function
has at most `len(compat_args)` arguments and whether or not all of these
elements in `args` are set to their default values.
fname: str
The name of the function being passed the `*args` parameter
args: tuple
The `*args` parameter passed into a function
max_fname_arg_count: int
The maximum number of arguments that the function `fname`
can accept, excluding those in `args`. Used for displaying
appropriate error messages. Must be non-negative.
compat_args: OrderedDict
A ordered dictionary of keys and their associated default values.
In order to accommodate buggy behaviour in some versions of `numpy`,
where a signature displayed keyword arguments but then passed those
arguments **positionally** internally when calling downstream
implementations, an ordered dictionary ensures that the original
order of the keyword arguments is enforced. Note that if there is
only one key, a generic dict can be passed in as well.
Raises
------
TypeError if `args` contains more values than there are `compat_args`
ValueError if `args` contains values that do not correspond to those
of the default values specified in `compat_args`
"""
_check_arg_length(fname, args, max_fname_arg_count, compat_args)
# We do this so that we can provide a more informative
# error message about the parameters that we are not
# supporting in the pandas implementation of 'fname'
kwargs = dict(zip(compat_args, args))
_check_for_default_values(fname, kwargs, compat_args)
def _check_for_invalid_keys(fname, kwargs, compat_args):
"""
Checks whether 'kwargs' contains any keys that are not
in 'compat_args' and raises a TypeError if there is one.
"""
# set(dict) --> set of the dictionary's keys
diff = set(kwargs) - set(compat_args)
if diff:
bad_arg = list(diff)[0]
raise TypeError(("{fname}() got an unexpected "
"keyword argument '{arg}'".
format(fname=fname, arg=bad_arg)))
def validate_kwargs(fname, kwargs, compat_args):
"""
Checks whether parameters passed to the **kwargs argument in a
function `fname` are valid parameters as specified in `*compat_args`
and whether or not they are set to their default values.
Parameters
----------
fname: str
The name of the function being passed the `**kwargs` parameter
kwargs: dict
The `**kwargs` parameter passed into `fname`
compat_args: dict
A dictionary of keys that `kwargs` is allowed to have and their
associated default values
Raises
------
TypeError if `kwargs` contains keys not in `compat_args`
ValueError if `kwargs` contains keys in `compat_args` that do not
map to the default values specified in `compat_args`
"""
kwds = kwargs.copy()
_check_for_invalid_keys(fname, kwargs, compat_args)
_check_for_default_values(fname, kwds, compat_args)
def validate_args_and_kwargs(fname, args, kwargs,
max_fname_arg_count,
compat_args):
"""
Checks whether parameters passed to the *args and **kwargs argument in a
function `fname` are valid parameters as specified in `*compat_args`
and whether or not they are set to their default values.
Parameters
----------
fname: str
The name of the function being passed the `**kwargs` parameter
args: tuple
The `*args` parameter passed into a function
kwargs: dict
The `**kwargs` parameter passed into `fname`
max_fname_arg_count: int
The minimum number of arguments that the function `fname`
requires, excluding those in `args`. Used for displaying
appropriate error messages. Must be non-negative.
compat_args: OrderedDict
A ordered dictionary of keys that `kwargs` is allowed to
have and their associated default values. Note that if there
is only one key, a generic dict can be passed in as well.
Raises
------
TypeError if `args` contains more values than there are
`compat_args` OR `kwargs` contains keys not in `compat_args`
ValueError if `args` contains values not at the default value (`None`)
`kwargs` contains keys in `compat_args` that do not map to the default
value as specified in `compat_args`
See Also
--------
validate_args : purely args validation
validate_kwargs : purely kwargs validation
"""
# Check that the total number of arguments passed in (i.e.
# args and kwargs) does not exceed the length of compat_args
_check_arg_length(fname, args + tuple(kwargs.values()),
max_fname_arg_count, compat_args)
# Check there is no overlap with the positional and keyword
# arguments, similar to what is done in actual Python functions
args_dict = dict(zip(compat_args, args))
for key in args_dict:
if key in kwargs:
raise TypeError("{fname}() got multiple values for keyword "
"argument '{arg}'".format(fname=fname, arg=key))
kwargs.update(args_dict)
validate_kwargs(fname, kwargs, compat_args)
def validate_bool_kwarg(value, arg_name):
""" Ensures that argument passed in arg_name is of type bool. """
if not (is_bool(value) or value is None):
raise ValueError('For argument "{arg}" expected type bool, received '
'type {typ}.'.format(arg=arg_name,
typ=type(value).__name__))
return value
def validate_axis_style_args(data, args, kwargs, arg_name, method_name):
"""Argument handler for mixed index, columns / axis functions
In an attempt to handle both `.method(index, columns)`, and
`.method(arg, axis=.)`, we have to do some bad things to argument
parsing. This translates all arguments to `{index=., columns=.}` style.
Parameters
----------
data : DataFrame or Panel
arg : tuple
All positional arguments from the user
kwargs : dict
All keyword arguments from the user
arg_name, method_name : str
Used for better error messages
Returns
-------
kwargs : dict
A dictionary of keyword arguments. Doesn't modify ``kwargs``
inplace, so update them with the return value here.
Examples
--------
>>> df._validate_axis_style_args((str.upper,), {'columns': id},
... 'mapper', 'rename')
{'columns': <function id>, 'index': <method 'upper' of 'str' objects>}
This emits a warning
>>> df._validate_axis_style_args((str.upper, id), {},
... 'mapper', 'rename')
{'columns': <function id>, 'index': <method 'upper' of 'str' objects>}
"""
# TODO(PY3): Change to keyword-only args and remove all this
out = {}
# Goal: fill 'out' with index/columns-style arguments
# like out = {'index': foo, 'columns': bar}
# Start by validating for consistency
if 'axis' in kwargs and any(x in kwargs for x in data._AXIS_NUMBERS):
msg = "Cannot specify both 'axis' and any of 'index' or 'columns'."
raise TypeError(msg)
# First fill with explicit values provided by the user...
if arg_name in kwargs:
if args:
msg = ("{} got multiple values for argument "
"'{}'".format(method_name, arg_name))
raise TypeError(msg)
axis = data._get_axis_name(kwargs.get('axis', 0))
out[axis] = kwargs[arg_name]
# More user-provided arguments, now from kwargs
for k, v in kwargs.items():
try:
ax = data._get_axis_name(k)
except ValueError:
pass
else:
out[ax] = v
# All user-provided kwargs have been handled now.
# Now we supplement with positional arguments, emitting warnings
# when there's ambiguity and raising when there's conflicts
if len(args) == 0:
pass # It's up to the function to decide if this is valid
elif len(args) == 1:
axis = data._get_axis_name(kwargs.get('axis', 0))
out[axis] = args[0]
elif len(args) == 2:
if 'axis' in kwargs:
# Unambiguously wrong
msg = ("Cannot specify both 'axis' and any of 'index' "
"or 'columns'")
raise TypeError(msg)
msg = ("Interpreting call\n\t'.{method_name}(a, b)' as "
"\n\t'.{method_name}(index=a, columns=b)'.\nUse named "
"arguments to remove any ambiguity. In the future, using "
"positional arguments for 'index' or 'columns' will raise "
" a 'TypeError'.")
warnings.warn(msg.format(method_name=method_name,), FutureWarning,
stacklevel=4)
out[data._AXIS_NAMES[0]] = args[0]
out[data._AXIS_NAMES[1]] = args[1]
else:
msg = "Cannot specify all of '{}', 'index', 'columns'."
raise TypeError(msg.format(arg_name))
return out
def validate_fillna_kwargs(value, method, validate_scalar_dict_value=True):
"""Validate the keyword arguments to 'fillna'.
This checks that exactly one of 'value' and 'method' is specified.
If 'method' is specified, this validates that it's a valid method.
Parameters
----------
value, method : object
The 'value' and 'method' keyword arguments for 'fillna'.
validate_scalar_dict_value : bool, default True
Whether to validate that 'value' is a scalar or dict. Specifically,
validate that it is not a list or tuple.
Returns
-------
value, method : object
"""
from pandas.core.missing import clean_fill_method
if value is None and method is None:
raise ValueError("Must specify a fill 'value' or 'method'.")
elif value is None and method is not None:
method = clean_fill_method(method)
elif value is not None and method is None:
if validate_scalar_dict_value and isinstance(value, (list, tuple)):
raise TypeError('"value" parameter must be a scalar or dict, but '
'you passed a "{0}"'.format(type(value).__name__))
elif value is not None and method is not None:
raise ValueError("Cannot specify both 'value' and 'method'.")
return value, method