CODEWITHSUNDEEP
pythongeneratorpython-itertools
Ruggero Turra
Ruggero Turra

Reputation: 17710

opposite of itertools.dropwhile (how to stop generators after N iteration)

is there a simple way to stop an iterator after N loops? Of course I can write something like:

for i, val in enumerate(gen()):
    if i > N: break

but I would like to write something like

for val in stop_after(gen(), N):
    ...

I tried with itertools.dropwhile but it seems to do the opposite. Of course I can rewrite itertools.dropwhile with the inverse logic, but I am wondering if there is something already implemented.

Upvotes: 1

Views: 620

Answers (2)

Dan D.
Dan D.

Reputation: 74655

Use islice:

for val in itertools.islice(gen(), N):
    ....

Assuming that your example was meant to be:

for i, val in enumerate(gen()):
    if i > N: break

Upvotes: 2

Eugene Soldatov
Eugene Soldatov

Reputation: 10145

I think you need itertools.takewhile:

https://docs.python.org/2/library/itertools.html#itertools.takewhile

Upvotes: 0

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