astype

Copies an array to a specified data type irrespective of type-promotion rules.

Parameters:

Name	Type	Description	Default
x		array to cast.	required
dtype		desired data type.	required
copy		specifies whether to copy an array when the specified dtype matches the data type of the input array x. If True, a newly allocated array is always returned. If False and the specified dtype matches the data type of the input array, the input array is returned; otherwise, a newly allocated array is returned. Default: True.	True

Notes

• When casting a boolean input array to a real-valued data type, a value of True is cast to a real-valued number equal to 1, and a value of False must cast to a real-valued number equal to 0.

• When casting a boolean input array to a complex floating-point data type, a value of True is cast to a complex number equal to 1 + 0j, and a value of False is cast to a complex number equal to 0 + 0j.

• When casting a real-valued input array to bool, a value of 0 is cast to False, and a non-zero value is cast to True.

• When casting a complex floating-point array to bool, a value of 0 + 0j is cast to False, and all other values are cast to True.

Returns:

Name	Type	Description
out	array	an array having the specified data type. The returned array has the same shape as x.

Examples:

>>> a = sparse.COO.from_numpy(np.array([[0, 1], [2, 0]]))
>>> o = sparse.astype(a, "float32")
>>> o.todense()
array([[0., 1.],
       [2., 0.]], dtype=float32)

Source code in sparse/numba_backend/_common.py

def astype(x, dtype, /, *, copy=True):
    """
    Copies an array to a specified data type irrespective of type-promotion rules.

    Parameters
    ----------
    x: array
        array to cast.
    dtype: dtype
        desired data type.
    copy: bool
        specifies whether to copy an array when the specified ``dtype`` matches the data type
        of the input array ``x``. If ``True``, a newly allocated array is always returned.
        If ``False`` and the specified ``dtype`` matches the data type of the input array,
        the input array is returned; otherwise, a newly allocated array is returned.
        Default: ``True``.

    Notes
    -----

       - When casting a boolean input array to a real-valued data type, a value of ``True`` is cast
         to a real-valued number equal to ``1``, and a value of ``False`` must cast to a real-valued
         number equal to ``0``.

       - When casting a boolean input array to a complex floating-point data type, a value of ``True``
       is cast to a complex number equal to ``1 + 0j``, and a value of ``False`` is cast to a complex
       number equal to ``0 + 0j``.

       - When casting a real-valued input array to ``bool``, a value of ``0`` is cast to ``False``,
       and a non-zero value is cast to ``True``.

       - When casting a complex floating-point array to ``bool``, a value of ``0 + 0j`` is cast
       to ``False``, and all other values are cast to ``True``.

    Returns
    -------
    out: array
        an array having the specified data type. The returned array has the same shape as ``x``.

    Examples
    --------
    >>> a = sparse.COO.from_numpy(np.array([[0, 1], [2, 0]]))
    >>> o = sparse.astype(a, "float32")
    >>> o.todense()  # doctest: +NORMALIZE_WHITESPACE
    array([[0., 1.],
           [2., 0.]], dtype=float32)
    """
    return x.astype(dtype, copy=copy)