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Fonction can_cast - module numpy

Signature de la fonction can_cast

Description

can_cast.__doc__

    can_cast(from_, to, casting='safe')

    Returns True if cast between data types can occur according to the
    casting rule.  If from is a scalar or array scalar, also returns
    True if the scalar value can be cast without overflow or truncation
    to an integer.

    Parameters
    ----------
    from_ : dtype, dtype specifier, scalar, or array
        Data type, scalar, or array to cast from.
    to : dtype or dtype specifier
        Data type to cast to.
    casting : {'no', 'equiv', 'safe', 'same_kind', 'unsafe'}, optional
        Controls what kind of data casting may occur.

          * 'no' means the data types should not be cast at all.
          * 'equiv' means only byte-order changes are allowed.
          * 'safe' means only casts which can preserve values are allowed.
          * 'same_kind' means only safe casts or casts within a kind,
            like float64 to float32, are allowed.
          * 'unsafe' means any data conversions may be done.

    Returns
    -------
    out : bool
        True if cast can occur according to the casting rule.

    Notes
    -----
    .. versionchanged:: 1.17.0
       Casting between a simple data type and a structured one is possible only
       for "unsafe" casting.  Casting to multiple fields is allowed, but
       casting from multiple fields is not.

    .. versionchanged:: 1.9.0
       Casting from numeric to string types in 'safe' casting mode requires
       that the string dtype length is long enough to store the maximum
       integer/float value converted.

    See also
    --------
    dtype, result_type

    Examples
    --------
    Basic examples

    >>> np.can_cast(np.int32, np.int64)
    True
    >>> np.can_cast(np.float64, complex)
    True
    >>> np.can_cast(complex, float)
    False

    >>> np.can_cast('i8', 'f8')
    True
    >>> np.can_cast('i8', 'f4')
    False
    >>> np.can_cast('i4', 'S4')
    False

    Casting scalars

    >>> np.can_cast(100, 'i1')
    True
    >>> np.can_cast(150, 'i1')
    False
    >>> np.can_cast(150, 'u1')
    True

    >>> np.can_cast(3.5e100, np.float32)
    False
    >>> np.can_cast(1000.0, np.float32)
    True

    Array scalar checks the value, array does not

    >>> np.can_cast(np.array(1000.0), np.float32)
    True
    >>> np.can_cast(np.array([1000.0]), np.float32)
    False

    Using the casting rules

    >>> np.can_cast('i8', 'i8', 'no')
    True
    >>> np.can_cast('<i8', '>i8', 'no')
    False

    >>> np.can_cast('<i8', '>i8', 'equiv')
    True
    >>> np.can_cast('<i4', '>i8', 'equiv')
    False

    >>> np.can_cast('<i4', '>i8', 'safe')
    True
    >>> np.can_cast('<i8', '>i4', 'safe')
    False

    >>> np.can_cast('<i8', '>i4', 'same_kind')
    True
    >>> np.can_cast('<i8', '>u4', 'same_kind')
    False

    >>> np.can_cast('<i8', '>u4', 'unsafe')
    True