Evaluate iterator in python

Question

I have a lazy iterator/generator a which is doing some side-effect on each iteration and I don't care about the values that it produces. What is the most idiomatic way to evaluate the side effects? Of course, I can simply do:

for _ in a: pass

But it seems rather ugly.

That's probably the least bad strategy, as generators with side effects aren't very idiomatic Python in the first place. — TigerhawkT3
– TigerhawkT3, Commented Nov 4, 2016 at 10:44
Better solution is don't write a lazy iterator with side effects — khelwood
– khelwood, Commented Nov 4, 2016 at 10:45
True, but in my case, the iterator comes from a library, unfortunately. — user1747134
– user1747134, Commented Nov 4, 2016 at 10:46
Could you give more context? It's likely there's another approach that would be altogether more idiomatic. Note: "Particularly tricky is map() invoked for the side effects of the function; the correct transformation is to use a regular for loop (since creating a list would just be wasteful)." — jonrsharpe
– jonrsharpe, Commented Nov 4, 2016 at 10:46
If the generator always yields truthy values: all(a). If it always yields falsy values: any(a). — jasonharper
– jasonharper, Commented Nov 4, 2016 at 13:42

Noelle L. · Accepted Answer · 2021-12-05 17:28:04Z

3

I found the recipe for the function consume() in itertools recipes section. Esentially, it recommends to do:

collections.deque(iterator, maxlen=0)

edited Dec 5, 2021 at 17:28

Noelle L.

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answered Nov 25, 2016 at 15:52

user1747134

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