shuffling.py

#!/usr/bin/env python3


# John's version.
def shuffle(deck):
  return [e for l in [a for a in zip(deck[:(len(deck)//2)], deck[(len(deck)//2):])] for e in l]


# Slightly simplified. Above, the inner comprehension has just "a for a" with no
# "if" at the end, so we can reduce it down to just the iterator.
def shuffle1(deck):
  half = len(deck) // 2
  return [e for l in zip(deck[:half], deck[half:]) for e in l]


deck = range(52)
shuffled = shuffle1(deck)
print(shuffled)
assert shuffle(deck) == shuffled