':type s: str
:type numRows: int
:rtype: str'

def convert(self, s, numRows):

    if (numRows == 1):
        return s
    (step, zigzag) = (((2 * numRows) - 2), '')
    for i in xrange(numRows):
        for j in xrange(i, len(s), step):
            zigzag += s[j]
            if ((0 < i < (numRows - 1)) and (((j + step) - (2 * i)) < len(s))):
                zigzag += s[((j + step) - (2 * i))]
    return zigzag
