NEW! Master Swift design patterns with my latest book! >>

How to split an array into chunks

Paul Hudson       @twostraws

If you have an array of elements and you want to split them into chunks of a size you specify, here’s a useful extension you can add to your code:

extension Array {
    func chunked(into size: Int) -> [[Element]] {
        return stride(from: 0, to: count, by: size).map {
            Array(self[$0 ..< Swift.min($0 + size, count)])
        }
    }
}

That converts an array into an array of arrays, using whatever size you specify. For example, if you have the numbers 1 to 100 in an array and you want to split it so that there are many arrays containing five numbers each, you’d write this:

let numbers = Array(1...100)
let result = numbers.chunked(into: 5)

Available from iOS 8.0

Did this solution work for you? Please pass it on!

Other people are reading…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

Love Hacking with Swift?

Get all 40 projects in PDF and HTML: buy the Hacking with Swift book! It contains over 1300 pages of hands-on Swift coding, and will really help boost your iOS career

MASTER SWIFT NOW
Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns Buy Practical iOS 11 Buy Swift Coding Challenges Buy Server-Side Swift (Vapor Edition) Buy Server-Side Swift (Kitura Edition) Buy Hacking with macOS Buy Advanced iOS Volume One Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with Swift Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let me know!

Click here to visit the Hacking with Swift store >>