import random def _uniform_rng(): while True: yield random.uniform(0, 1) _rng = _uniform_rng() def poprandom(sequence, rng=_rng): index = int(round(next(rng) * (len(sequence) - 1))) item = sequence[index] # It's O(1) to pop the last item, and O(n) to pop any other item. So we'll # always pop the last item and put it in the slot vacated by the item we're # popping. last_item = sequence.pop() if index < len(sequence): sequence[index] = last_item return item def is_all_zeroes(sequence): return all(item == 0 for item in sequence)