Inzynierka/Lib/site-packages/pandas/core/arrays/floating.py
2023-06-02 12:51:02 +02:00

160 lines
3.8 KiB
Python

from __future__ import annotations
import numpy as np
from pandas.core.dtypes.base import register_extension_dtype
from pandas.core.dtypes.common import is_float_dtype
from pandas.core.arrays.numeric import (
NumericArray,
NumericDtype,
)
class FloatingDtype(NumericDtype):
"""
An ExtensionDtype to hold a single size of floating dtype.
These specific implementations are subclasses of the non-public
FloatingDtype. For example we have Float32Dtype to represent float32.
The attributes name & type are set when these subclasses are created.
"""
_default_np_dtype = np.dtype(np.float64)
_checker = is_float_dtype
@classmethod
def construct_array_type(cls) -> type[FloatingArray]:
"""
Return the array type associated with this dtype.
Returns
-------
type
"""
return FloatingArray
@classmethod
def _str_to_dtype_mapping(cls):
return FLOAT_STR_TO_DTYPE
@classmethod
def _safe_cast(cls, values: np.ndarray, dtype: np.dtype, copy: bool) -> np.ndarray:
"""
Safely cast the values to the given dtype.
"safe" in this context means the casting is lossless.
"""
# This is really only here for compatibility with IntegerDtype
# Here for compat with IntegerDtype
return values.astype(dtype, copy=copy)
class FloatingArray(NumericArray):
"""
Array of floating (optional missing) values.
.. versionadded:: 1.2.0
.. warning::
FloatingArray is currently experimental, and its API or internal
implementation may change without warning. Especially the behaviour
regarding NaN (distinct from NA missing values) is subject to change.
We represent a FloatingArray with 2 numpy arrays:
- data: contains a numpy float array of the appropriate dtype
- mask: a boolean array holding a mask on the data, True is missing
To construct an FloatingArray from generic array-like input, use
:func:`pandas.array` with one of the float dtypes (see examples).
See :ref:`integer_na` for more.
Parameters
----------
values : numpy.ndarray
A 1-d float-dtype array.
mask : numpy.ndarray
A 1-d boolean-dtype array indicating missing values.
copy : bool, default False
Whether to copy the `values` and `mask`.
Attributes
----------
None
Methods
-------
None
Returns
-------
FloatingArray
Examples
--------
Create an FloatingArray with :func:`pandas.array`:
>>> pd.array([0.1, None, 0.3], dtype=pd.Float32Dtype())
<FloatingArray>
[0.1, <NA>, 0.3]
Length: 3, dtype: Float32
String aliases for the dtypes are also available. They are capitalized.
>>> pd.array([0.1, None, 0.3], dtype="Float32")
<FloatingArray>
[0.1, <NA>, 0.3]
Length: 3, dtype: Float32
"""
_dtype_cls = FloatingDtype
# The value used to fill '_data' to avoid upcasting
_internal_fill_value = np.nan
# Fill values used for any/all
# Incompatible types in assignment (expression has type "float", base class
# "BaseMaskedArray" defined the type as "<typing special form>")
_truthy_value = 1.0 # type: ignore[assignment]
_falsey_value = 0.0 # type: ignore[assignment]
_dtype_docstring = """
An ExtensionDtype for {dtype} data.
This dtype uses ``pd.NA`` as missing value indicator.
Attributes
----------
None
Methods
-------
None
"""
# create the Dtype
@register_extension_dtype
class Float32Dtype(FloatingDtype):
type = np.float32
name = "Float32"
__doc__ = _dtype_docstring.format(dtype="float32")
@register_extension_dtype
class Float64Dtype(FloatingDtype):
type = np.float64
name = "Float64"
__doc__ = _dtype_docstring.format(dtype="float64")
FLOAT_STR_TO_DTYPE = {
"float32": Float32Dtype(),
"float64": Float64Dtype(),
}