NEW: Got a question? Get help on our new forums! >>

How to use one-sided ranges

Swift version: 5.1

Paul Hudson    @twostraws   

One-sided ranges allow us to skip either the start or end of a range to have Swift infer the starting point for us. As an example, consider this array:

let characters = ["Dr Horrible", "Captain Hammer", "Penny", "Bad Horse", "Moist"]

If we wanted to read only the first three items from that array, we could use characters[..<3] – we skipped the start point, so Swift will automatically infer the start of the array:

let bigParts = characters[..<3]

That will create an array containing ["Dr Horrible", "Captain Hammer", "Penny"].

Similarly, we could skip the end of the range to have Swift infer the end of the array, like this:

let smallParts = characters[3...]

That will create an array containing ["Bad Horse", "Moist"].

Hacking with Swift is sponsored by Instabug

SPONSORED Catch bugs as soon as they happen and know exactly why a crash occurred by integrating Instabug's SDK in one minute. You will automatically receive device data, network logs, and reproduction steps with every bug and crash report.

Learn more and get started for free

Sponsor Hacking with Swift and reach the world's largest Swift community!

Support my work on Patreon

Available from iOS 8.0

Similar solutions…

About the Swift Knowledge Base

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

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 5.0/5