itertools_roundrobin_generator_cycling_multiple_iterables.py

1from itertools import cycle, islice
2
3def roundrobin(*iterables):
4    "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
5    # Recipe credited to George Sakkis
6    num_active = len(iterables)
7    nexts = cycle(iter(it).__next__ for it in iterables)
8    while num_active:
9        try:
10            for next_el in nexts:
11                yield next_el()
12        except StopIteration:
13            # Remove the exhausted iterator from the cycle.
14            num_active -= 1
15            nexts = cycle(islice(nexts, num_active))
16
17# Example usage:
18if __name__ == "__main__":
19    result = list(roundrobin('ABC', 'D', 'EF'))
20    print(result)