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

This is simple enough although not nearly as flexible as roundrobin:

def paired(it1, it2):
    it2 = iter(it2)
    for item in it1:
        yield item
        yield next(it2)

tested in 2.7.5:

>>> x = [0, 1, 2]
>>> y = [3, 4]
>>> print list(paired(x, y))
[0, 3, 1, 4, 2]

Note that it stops as soon as the list y runs out (because next(it2) raises StopIteration).