numerictypes.py 文件源码

def issubdtype(arg1, arg2):
    """
    Returns True if first argument is a typecode lower/equal in type hierarchy.

    Parameters
    ----------
    arg1, arg2 : dtype_like
        dtype or string representing a typecode.

    Returns
    -------
    out : bool

    See Also
    --------
    issubsctype, issubclass_
    numpy.core.numerictypes : Overview of numpy type hierarchy.

    Examples
    --------
    >>> np.issubdtype('S1', str)
    True
    >>> np.issubdtype(np.float64, np.float32)
    False

    """
    if issubclass_(arg2, generic):
        return issubclass(dtype(arg1).type, arg2)
    mro = dtype(arg2).type.mro()
    if len(mro) > 1:
        val = mro[1]
    else:
        val = mro[0]
    return issubclass(dtype(arg1).type, val)


# This dictionary allows look up based on any alias for an array data-type