The way iterators work in Python, there is the following (potentially surprising) behavior: >>> l = [1, 2, 3] >>> g = (x for x in l) >>> list(g) [1, 2, 3] >>> list(g) [] That is, iterators are “used up” during the iteration and will not return items again which have already been iterated over. Un…

[image] lmtzx9h4qqnt: But is this really always the case? I think there are a few exceptions for cases that involve iterating over streaming data. e.g. the eachline iterator is documented as closing the file at the end of iteration, so it is isempty if you try to iterate a second time.

Is it always safe to “re-use” an iterator/generator?

General Usage

lmtzx9h4qqnt March 15, 2023, 2:21am 10

A relevant previous discussion:

Topic		Replies	Views
Iterators.Stateful is not an iterator? New to Julia	8	1856	March 1, 2022
From generator (with Channel) to iterator General Usage	6	2611	April 24, 2018
Yield in iterator General Usage	5	1129	November 28, 2023
Does length(itr) need to be invariant? (stateful iterator) General Usage question , iterators	4	162	September 24, 2024
`isempty(enumerate(Iterators.Stateful(...)))` advances the stateful iterator? General Usage	3	432	November 16, 2021

Is it always safe to “re-use” an iterator/generator?

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