gistfile1.py

import sys
import pdb


# iterate over 'blocksize' elems of a list at once.
def blocks(xs, blocksize):
    for i in xrange(0, len(xs), blocksize):
        yield xs[i:i+blocksize]


# partitions a list into groups of length blocksize.  E.g.:
def blocklist(xs, blocksize):
    return list(blocks(xs, blocksize))
assert(blocklist([1, 2, 3, 4, 5, 6], 2) == [[1, 2], [3, 4], [5, 6]])
assert(blocklist([1, 2, 3, 4, 5, 6], 3) == [[1, 2, 3], [4, 5, 6]])
assert(blocklist([1, 2, 3, 4, 5, 6], 4) == [[1, 2, 3, 4], [5, 6]])


def process(files):
    fileslines = []
    for filename in files:
        with open(filename, 'rb') as f:
            fileslines.append(f.readlines())


    filesgroups = [blocklist(x, 5) for x in fileslines]
    for groups in zip(*filesgroups):
        for group in groups:
            for line in group:
                print line


process(sys.argv[1:])