can list comprehensions replace map?

[Christopher Subich]

Andrew Dalke wrote:
> Steven Bethard wrote:
> 
>>Here's one possible solution:
>>
>>py> import itertools as it
>>py> def zipfill(*lists):
>>... 	max_len = max(len(lst) for lst in lists)
> 
> 
> A limitation to this is the need to iterate over the
> lists twice, which might not be possible if one of them
> is a file iterator.
> 
> Here's a clever, though not (in my opinion) elegant solution
> 
> import itertools
> 
> def zipfill(*seqs):
>     count = [len(seqs)]
>     def _forever(seq):
>         for item in seq: yield item
>         count[0] -= 1
>         while 1: yield None
>     seqs = [_forever(seq) for seq in seqs]
>     while 1:
>         x = [seq.next() for seq in seqs]
>         if count == [0]:
>             break
>         yield x

I like this solution best (note, it doesn't actually use itertools).  My 
naive solution:
def lzip(*args):
    ilist = [iter(a) for a in args]
    while 1:
       res = []
       count = 0
       for i in ilist:
          try:
             g = i.next()
             count += 1
          except StopIteration: # End of iter
             g = None
          res.append(g)
       if count > 0: # At least one iter wasn't finished
          yield tuple(res)
       else: # All finished
          raise StopIteration