How Python's zip pairs lists

pythoniteration

zip walks several lists in step, taking the item at the same position from each and yielding them together as a tuple. It stops as soon as the shortest list runs out, so the leftover items of longer lists are never read.

def pair_up(a, b):
    pairs = []
    for left, right in zip(a, b):
        pairs.append((left, right))
    return pairs