[Python-ideas] An exhaust() function for iterators

[Raymond Hettinger]

On Sep 28, 2013, at 9:06 PM, Clay Sweetser <clay.sweetser at gmail.com> wrote:

> 
> As it turns out, the fastest and most efficient method available in
> the standard library is collections.deque's __init__ and extend
> methods.


That technique is shown in the itertools docs in the consume() recipe.
It is the fastest way in CPython (in PyPy, a straight for-loop will
likely be the fastest).

I didn't immortalize it as a real itertool because I think most code is
better-off with a straight for-loop.

The itertools were inspired by functional languages and intended
to be used in a functional style where iterators with side-effects
would be considered bad form.

A regular for-loop is only a little bit slower, but it has a number of virtues
including clarity, signal checking, and thread switching.

In a real application, the speed difference of consume() vs a for-loop
is likely to be insignificant if the iterator is doing anything interesting at all.


Raymond



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