with its elements centered in a string of
    length `width`.

    Calls `str.center` element-wise.

    Parameters
    ----------
    a : array_like of str or unicode

    width : int
        The length of the resulting strings
    fillchar : str or unicode, optional
        The padding character to use (default is space).

    Returns
    -------
    out : ndarray
        Output array of str or unicode, depending on input
        types

    See Also
    --------
    str.center
    
    Notes
    -----
    This function is intended to work with arrays of strings.  The
    fill character is not applied to numeric types.

    Examples
    --------
    >>> c = np.array(['a1b2','1b2a','b2a1','2a1b']); c
    array(['a1b2', '1b2a', 'b2a1', '2a1b'], dtype='<U4')
    >>> np.char.center(c, width=9)
    array(['   a1b2  ', '   1b2a  ', '   b2a1  ', '   2a1b  '], dtype='<U9')
    >>> np.char.center(c, width=9, fillchar='*')
    array(['***a1b2**', '***1b2a**', '***b2a1**', '***2a1b**'], dtype='<U9')
    >>> np.char.center(c, width=1)
    array(['a', '1', 'b', '2'], dtype='<U1')

    r