numpy multiply function

from_defchararray.py

def multiply(a, i):
    """
    Return (a * i), that is string multiple concatenation,
    element-wise.

    Values in `i` of less than 0 are treated as 0 (which yields an
    empty string).

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

    i : array_like of ints

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

    """
    a_arr = numpy.asarray(a)
    i_arr = numpy.asarray(i)
    if not issubclass(i_arr.dtype.type, integer):
        raise ValueError("Can only multiply by integers")
    out_size = _get_num_chars(a_arr) * max(long(i_arr.max()), 0)
    return _vec_string(
        a_arr, (a_arr.dtype.type, out_size), '__mul__', (i_arr,))