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

Enum raw values

Sometimes you need to be able to assign values to enums so they have meaning. This lets you create them dynamically, and also use them in different ways.

For example, you might create a Planet enum that stores integer values for each of its cases:

enum Planet: Int {
    case mercury
    case venus
    case earth
    case mars
}

Swift will automatically assign each of those a number starting from 0, and you can use that number to create an instance of the appropriate enum case. For example, earth will be given the number 2, so you can write this:

let earth = Planet(rawValue: 2)

If you want, you can assign one or more cases a specific value, and Swift will generate the rest. It’s not very natural for us to think of Earth as the second planet, so you could write this:

enum Planet: Int {
    case mercury = 1
    case venus
    case earth
    case mars
}

Now Swift will assign 1 to mercury and count upwards from there, meaning that earth is now the third planet.

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: 4.5/5

Link copied to your pasteboard.