defchararray.py 文件源码

def lower(a):
    """
    Return an array with the elements converted to lowercase.

    Call `str.lower` element-wise.

    For 8-bit strings, this method is locale-dependent.

    Parameters
    ----------
    a : array_like, {str, unicode}
        Input array.

    Returns
    -------
    out : ndarray, {str, unicode}
        Output array of str or unicode, depending on input type

    See also
    --------
    str.lower

    Examples
    --------
    >>> c = np.array(['A1B C', '1BCA', 'BCA1']); c
    array(['A1B C', '1BCA', 'BCA1'],
          dtype='|S5')
    >>> np.char.lower(c)
    array(['a1b c', '1bca', 'bca1'],
          dtype='|S5')

    """
    a_arr = numpy.asarray(a)
    return _vec_string(a_arr, a_arr.dtype, 'lower')