python merge two lists (even/odd elements)

Question

Given two lists, I want to merge them so that all elements from the first list are even-indexed (preserving their order) and all elements from second list are odd-indexed (a

Answer 1

Use the roundrobin recipe from itertools:

from itertools import cycle, islice
def roundrobin(*iterables):
    "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
    # Recipe credited to George Sakkis
    pending = len(iterables)
    nexts = cycle(iter(it).next for it in iterables)
    while pending:
        try:
            for next in nexts:
                yield next()
        except StopIteration:
            pending -= 1
            nexts = cycle(islice(nexts, pending))
>>> list(roundrobin(x,y))
[0, 3, 1, 4, 2]