116 lines
3.6 KiB
Python
116 lines
3.6 KiB
Python
from __future__ import annotations
|
|
|
|
import weakref
|
|
|
|
|
|
class Flags:
|
|
"""
|
|
Flags that apply to pandas objects.
|
|
|
|
.. versionadded:: 1.2.0
|
|
|
|
Parameters
|
|
----------
|
|
obj : Series or DataFrame
|
|
The object these flags are associated with.
|
|
allows_duplicate_labels : bool, default True
|
|
Whether to allow duplicate labels in this object. By default,
|
|
duplicate labels are permitted. Setting this to ``False`` will
|
|
cause an :class:`errors.DuplicateLabelError` to be raised when
|
|
`index` (or columns for DataFrame) is not unique, or any
|
|
subsequent operation on introduces duplicates.
|
|
See :ref:`duplicates.disallow` for more.
|
|
|
|
.. warning::
|
|
|
|
This is an experimental feature. Currently, many methods fail to
|
|
propagate the ``allows_duplicate_labels`` value. In future versions
|
|
it is expected that every method taking or returning one or more
|
|
DataFrame or Series objects will propagate ``allows_duplicate_labels``.
|
|
|
|
Notes
|
|
-----
|
|
Attributes can be set in two ways
|
|
|
|
>>> df = pd.DataFrame()
|
|
>>> df.flags
|
|
<Flags(allows_duplicate_labels=True)>
|
|
>>> df.flags.allows_duplicate_labels = False
|
|
>>> df.flags
|
|
<Flags(allows_duplicate_labels=False)>
|
|
|
|
>>> df.flags['allows_duplicate_labels'] = True
|
|
>>> df.flags
|
|
<Flags(allows_duplicate_labels=True)>
|
|
"""
|
|
|
|
_keys = {"allows_duplicate_labels"}
|
|
|
|
def __init__(self, obj, *, allows_duplicate_labels) -> None:
|
|
self._allows_duplicate_labels = allows_duplicate_labels
|
|
self._obj = weakref.ref(obj)
|
|
|
|
@property
|
|
def allows_duplicate_labels(self) -> bool:
|
|
"""
|
|
Whether this object allows duplicate labels.
|
|
|
|
Setting ``allows_duplicate_labels=False`` ensures that the
|
|
index (and columns of a DataFrame) are unique. Most methods
|
|
that accept and return a Series or DataFrame will propagate
|
|
the value of ``allows_duplicate_labels``.
|
|
|
|
See :ref:`duplicates` for more.
|
|
|
|
See Also
|
|
--------
|
|
DataFrame.attrs : Set global metadata on this object.
|
|
DataFrame.set_flags : Set global flags on this object.
|
|
|
|
Examples
|
|
--------
|
|
>>> df = pd.DataFrame({"A": [1, 2]}, index=['a', 'a'])
|
|
>>> df.flags.allows_duplicate_labels
|
|
True
|
|
>>> df.flags.allows_duplicate_labels = False
|
|
Traceback (most recent call last):
|
|
...
|
|
pandas.errors.DuplicateLabelError: Index has duplicates.
|
|
positions
|
|
label
|
|
a [0, 1]
|
|
"""
|
|
return self._allows_duplicate_labels
|
|
|
|
@allows_duplicate_labels.setter
|
|
def allows_duplicate_labels(self, value: bool) -> None:
|
|
value = bool(value)
|
|
obj = self._obj()
|
|
if obj is None:
|
|
raise ValueError("This flag's object has been deleted.")
|
|
|
|
if not value:
|
|
for ax in obj.axes:
|
|
ax._maybe_check_unique()
|
|
|
|
self._allows_duplicate_labels = value
|
|
|
|
def __getitem__(self, key):
|
|
if key not in self._keys:
|
|
raise KeyError(key)
|
|
|
|
return getattr(self, key)
|
|
|
|
def __setitem__(self, key, value) -> None:
|
|
if key not in self._keys:
|
|
raise ValueError(f"Unknown flag {key}. Must be one of {self._keys}")
|
|
setattr(self, key, value)
|
|
|
|
def __repr__(self) -> str:
|
|
return f"<Flags(allows_duplicate_labels={self.allows_duplicate_labels})>"
|
|
|
|
def __eq__(self, other):
|
|
if isinstance(other, type(self)):
|
|
return self.allows_duplicate_labels == other.allows_duplicate_labels
|
|
return False
|