# rust-itertools/itertools

Extra iterator adaptors, iterator methods, free functions, and macros.

Repository: https://github.com/rust-itertools/itertools
Canonical: https://ross.abutalabs.com/products/itertools
Homepage: https://docs.rs/itertools/
Language: Rust
License: Apache-2.0
License Family: permissive
Topics: rust, iterators
Last push: 2026-08-20T04:34:16+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 35, longevity 100
- inputs: {"age_days": 4419, "days_push": 13, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3161, forks 356 (observed 2026-08-28T04:07:46.529358+00:00)

## What it is
A Rust crate providing extra iterator adaptors, iterator methods, free functions, and macros via the Itertools trait. It extends Rust's standard Iterator with combinators like interleave, cartesian products, merging, grouping, and joining.

## Use cases
- interleave two iterators in Rust
- compute cartesian product of iterators
- group and chunk iterator elements
- merge sorted iterators lazily
- join iterator elements into a string
- extend Rust iterators with extra combinators

## When to choose
- you need iterator combinators beyond the Rust standard library
- you want a mature, zero-cost, widely-used utility crate (1.4B+ downloads)
- you need no_std support with the use_alloc feature

## When to avoid
- your needs are fully covered by std Iterator methods
- you want async or parallel iteration (use futures or rayon instead)

## Facets
- artifact type: library
- maturity: stable
- function: developer-tools
- domain: developer-tools
- platform: rust
- tags: iterators, iterators-adaptors, no-std, rust-crate, functional-programming, algorithms

## Member repositories
- rust-itertools/itertools (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:46.529358+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:25:14.416980+00:00, confidence not recorded.
  - readme: https://github.com/rust-itertools/itertools (fetched 2026-08-28T04:07:46.529358+00:00, sha b05ce16c04a2)
  - homepage: https://docs.rs/itertools/ (fetched 2026-08-29T09:40:01.010234+00:00, sha fee192e4ee75)
  - site_page: https://docs.rs/ (fetched 2026-08-29T09:40:01.015000+00:00, sha 756a1aaf7234)
  - site_page: https://docs.rs/crate/itertools/latest (fetched 2026-08-29T09:40:01.017677+00:00, sha 08dc88583369)
  - site_page: https://docs.rs/crate/itertools/latest/features (fetched 2026-08-29T09:40:01.019921+00:00, sha f1486d2d3cfa)
  - site_page: https://docs.rs/about (fetched 2026-08-29T09:40:01.022045+00:00, sha 29ab7986fbf5)
  - site_page: https://docs.rs/about/badges (fetched 2026-08-29T09:40:01.024221+00:00, sha 6588cac258af)
  - site_page: https://docs.rs/about/builds (fetched 2026-08-29T09:40:01.026391+00:00, sha 811231ca4680)
  - site_page: https://docs.rs/about/metadata (fetched 2026-08-29T09:40:01.029294+00:00, sha 0dcdccb2b2b2)
  - site_page: https://docs.rs/about/redirections (fetched 2026-08-29T09:40:01.032091+00:00, sha 1b1efd93105f)
- Data as of 2026-08-30T08:39:29.467469+00:00.