Custom Zip Longest Implementation

This function implements similar functionality to itertools.zip_longest, merging multiple iterable objects into an iterator. If the iterables are of unequal length, it fills the shorter ones with fillvalue.

Technology Stack : itertools, collections

Code Type : Function

Code Difficulty : Intermediate

                
                    
def zip_longest(*args, fillvalue=0):
    from itertools import zip_longest
    from collections import deque

    def fill_deques(deques, fillvalue):
        for deque_ in deques:
            while len(deque_) < len(args):
                deque_.append(fillvalue)

    def generate():
        deques = [deque(arg) for arg in args]
        fill_deques(deques, fillvalue)
        while True:
            yield [deque_.popleft() for deque_ in deques]
            fill_deques(deques, fillvalue)

    return generate()