How do I merge two python iterators?

You can do something that is almost exaclty what @Pramod first suggested.

def izipmerge(a, b):
  for i, j in itertools.izip(a,b):
    yield i
    yield j

The advantage of this approach is that you won't run out of memory if both a and b are infinite.

I also agree that itertools is not needed.

But why stop at 2?

  def tmerge(*iterators):
    for values in zip(*iterators):
      for value in values:
        yield value

handles any number of iterators from 0 on upwards.

UPDATE: DOH! A commenter pointed out that this won't work unless all the iterators are the same length.

The correct code is:

def tmerge(*iterators):
  empty = {}
  for values in itertools.zip_longest(*iterators, fillvalue=empty):
    for value in values:
      if value is not empty:
        yield value

and yes, I just tried it with lists of unequal length, and a list containing {}.

A generator will solve your problem nicely.

def imerge(a, b):
    for i, j in itertools.izip(a,b):
        yield i
        yield j