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

[Serhiy Storchaka]

On 25.02.13 20:53, Antoine Pitrou wrote:
>>> def test_lookahead():
>>>       it = iter('abc')
>>>       while True:
>>>           it, peeking = itertools.tee(it)
>>
>> This should be outside a loop.
>
> Only if you restrict yourself to access peeking each time you access it.
> (which, I suppose, is not the general use case for the lookahead
> proposal)

Only if your do not want to consume O(N) memory and spend O(N**2) time.