Commonly used sequence and collection algorithms for Swift

What's New

Swift Algorithms 1.2.0



  • Sequences have new grouped(by:) and keyed(by:) methods, which simplify building dictionaries based on sequence elements: (#197)

    let evensOdds = (1...10).grouped(by: { $0.isMultiple(of: 2) ? "even" : "odd" })
    // ["even": [2, 4, 6, 8, 10], "odd": [1, 3, 5, 7, 9]]
    let animals = ["Aardvark", "Alpaca", "Armadillo", "Barracuda", "Buffalo", ...]
    let alphaAnimals = animals.keyed(by: \.first!, resolvingConflictsWith: { _, first, _ in first })
    // ["A": "Aardvark", "B": "Barracuda", ...]
  • The endOfPrefix(while:) and startOfSuffix(while) methods are now public. These methods were previously implementation details of the trimming group of methods. (#211)


  • Documentation and performance improvements. (#202, #210)

The 1.2.0 release includes contributions from @amomchilov, @mattyoung, @natecook1000, @stephentyrone, and @ttsugriy.
Thank you!

Swift Algorithms

Swift Algorithms is an open-source package of sequence and collection algorithms, along with their related types.


The Algorithms package provides a variety of sequence and collection operations, letting you cycle over a collection's elements, find combinations and permutations, create a random sample, and more.

For example, the package includes a group of "chunking" methods, each of which breaks a collection into consecutive subsequences. One version tests adjacent elements to find the breaking point between chunks — you can use it to quickly separate an array into ascending runs:

let numbers = [10, 20, 30, 10, 40, 40, 10, 20]
let chunks = numbers.chunked(by: { $0 <= $1 })
// [[10, 20, 30], [10, 40, 40], [10, 20]]

Another version looks for a change in the transformation of each successive value. You can use that to separate a list of names into groups by the first character:

let names = ["Cassie", "Chloe", "Jasmine", "Jordan", "Taylor"]
let chunks = names.chunked(on: \.first)
// [["Cassie", "Chloe"], ["Jasmine", "Jordan"], ["Taylor"]]

Explore more chunking methods and the remainder of the Algorithms package in the links below.


For API documentation, see the library's official documentation in Xocde or on the Web.

Adding Swift Algorithms as a Dependency

To use the Algorithms library in a SwiftPM project, add the following line to the dependencies in your Package.swift file:

.package(url: "https://github.com/apple/swift-algorithms", from: "1.2.0"),

Include "Algorithms" as a dependency for your executable target:

.target(name: "<target>", dependencies: [
    .product(name: "Algorithms", package: "swift-algorithms"),

Finally, add import Algorithms to your source code.

Source Stability

The Swift Algorithms package is source stable; version numbers follow Semantic Versioning. Source breaking changes to public API can only land in a new major version.

The public API of the swift-algorithms package consists of non-underscored declarations that are marked public in the Algorithms module. Interfaces that aren't part of the public API may continue to change in any release, including patch releases.

Future minor versions of the package may introduce changes to these rules as needed.

We'd like this package to quickly embrace Swift language and toolchain improvements that are relevant to its mandate. Accordingly, from time to time, we expect that new versions of this package will require clients to upgrade to a more recent Swift toolchain release. Requiring a new Swift release will only require a minor version bump.


  • Swift Tools 5.4.0
View More Packages from this Author


Last updated: Fri Apr 12 2024 19:03:05 GMT-0900 (Hawaii-Aleutian Daylight Time)