Perfect card shuffling example

shuffle.py

#!/usr/bin/env python

decks = [range(1, 53)]

def shuffle(deck):
    a = deck[:len(deck)/2]
    b = deck[len(deck)/2:]
    c = zip(a, b)
    return c

print "Initial deck:"
print decks[-1]

for i in range(8):
    pairs = shuffle(decks[-1])
    decks.append(list(sum(pairs, ())))
    print
    print "Iteration: %d" % (i+1)
    print decks[-1]

print
print "Final deck:"
print decks[-1]