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Iterator Indexing #73482
Description
Itertools is considering a PR introducing iterator indexing, implemented in the same manner as the core library's slice indexing mechanism. This playground link demonstrates the gist of it:
// `Itertools::get` indexes an iterator:
assert_eq!(
(0..5).get(2).collect::<Vec<_>>(),
vec![2]
);
assert_eq!(
(0..5).get(..3).collect::<Vec<_>>(),
vec![0, 1, 2]
);
assert_eq!(
(0..5).get(2..).collect::<Vec<_>>(),
vec![2, 3, 4]
);I'm excited to merge this—it feels like something that ought to be in the standard library—but I want to avoid another {Itertools,Iterator}::flatten debacle; i.e., if the core library later adopts this same method, then itertools users calling this method will have builds break.
Would this addition be a good fit for the core library?
Activity
leonardo-m commentedon Jun 18, 2020
Sounds awesome. It's similar to python itertools.islice function. But I'd like to use the normal array slicing syntax. After this we need a built-in way to match on iterators, and the basic needs are covered.
cuviper commentedon Jun 18, 2020
The problem is that operator
Indexonly returns&Output, andIndexMutreturns&mut Output, so you can't create a new value for the indexing result.lachlansneff commentedon Jun 18, 2020
An
IndexableItertrait seems like an interesting idea.