getting an index in a for loop

[Erik Max Francis]

Paul Rubin wrote:

> Do they really???  I would have hoped that enumerate would build an
> iterator, something like
> 
>   def enumerate(seq):
>      i = 0
>      for s in seq:
>         yield s

well, yield i, s, yeah.

>         i += 1
> 
> If enumerate really does build the whole list, either I'm missing
> something basic or else there was a big blunder.

Err, you're right, it does:

>>> enumerate(range(5))
<enumerate object at 0x401aa0ec>
>>> list(_)
[(0, 0), (1, 1), (2, 2), (3, 3), (4, 4)]

My bad, that was just a misunderstanding on my part.  However, enumerate
is still only available in 2.3 so it's not really widely available yet.

The second form he suggested (that of building a second list with range
and zipping the two together) does, however, require building the entire
list, so my objection still applies to that one.

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