[Python-ideas] Add lookahead iterator (peeker) to itertools

[Serhiy Storchaka]

On 25.02.13 12:07, Antoine Pitrou wrote:
> Le Sun, 24 Feb 2013 22:41:48 -0500,
> Terry Reedy <tjreedy at udel.edu> a écrit :
>>
>> def test_lookahead():
>>       it = lookahead('abc')
>>       while it:
>>           a = it.peek
>>           b = next(it)
>>           print('next:', b, '; is peek:', a is b )
>
> def test_lookahead():
>      it = iter('abc')
>      while True:
>          it, peeking = itertools.tee(it)

This should be outside a loop.

>          try:
>              a = next(peeking)
>          except StopIteration:
>              break
>          b = next(it)
>          print('next:', b, '; is peek:', a is b )