NEW: Join my free 100 Days of SwiftUI challenge today! >>

What is the ternary operator?

Swift version: 5.1

Paul Hudson    @twostraws   

The ternary operator allows you to run a check and return one of two values depending on the result of that check – it has the name “ternary” because it works with three values rather than two or one like other operators. You’ll often see it written as ?: but in practice the ? and : are used separately.

Like I said, the ternary operator is used with three values: the check to run, what to return if the check is true, and what to return if the check is false. For example, if we had a score constant that contained an integer, we could make a result constant equal either to “Pass” or “Fail” depending on the value of score:

let score = 88
let result = score > 85 ? "Pass" : "Fail"

You can read that ternary as “if score is greater than 85 return Pass otherwise return Fail.” Because score was set to 88, result will be set to Pass.

The ternary operator usually makes your code harder to read and understand, so it doesn’t get much use.

LEARN SWIFTUI FOR FREE I have a massive, free SwiftUI video collection on YouTube teaching you how to build complete apps with SwiftUI – check it out!

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: 4.6/5