NEW: Subscribe to Hacking with Swift+ and accelerate your learning! >>

Computed properties

We just created a Sport struct like this:

struct Sport {
    var name: String
}

That has a name property that stores a String. These are called stored properties, because Swift has a different kind of property called a computed property – a property that runs code to figure out its value.

We’re going to add another stored property to the Sport struct, then a computed property. Here’s how that looks:

struct Sport {
    var name: String
    var isOlympicSport: Bool

    var olympicStatus: String {
        if isOlympicSport {
            return "\(name) is an Olympic sport"
        } else {
            return "\(name) is not an Olympic sport"
        }
    }
}

As you can see, olympicStatus looks like a regular String, but it returns different values depending on the other properties.

We can try it out by creating a new instance of Sport:

let chessBoxing = Sport(name: "Chessboxing", isOlympicSport: false)
print(chessBoxing.olympicStatus)
Hacking with Swift is sponsored by Instabug

SPONSORED Are you tired of wasting time debugging your Swift app? Instabug’s SDK is here to help you minimize debugging time by providing you with complete device details, network logs, and reproduction steps with every bug report. All data is attached automatically, and it only takes a line of code to setup. Start your free trial now and get 3 months off exclusively for the Hacking with Swift Community.

Start your free trial!

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

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: 4.7/5

Link copied to your pasteboard.