Notice: Undefined index: understanding-swift in /var/sites/hackingwithswift.com/site/src/Controller/NewBooksReadController.php on line 89
When would you use self in a method? - a free tutorial

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

When would you use self in a method?

Paul Hudson    @twostraws   

Inside a method, Swift lets us refer to the current instance of a struct using self, but broadly speaking you don’t want to unless you specifically need to distinguish what you mean.

By far the most common reason for using self is inside an initializer, where your likely to want parameter names that match the property names of your type, like this:

struct Student {
    var name: String
    var bestFriend: String

    init(name: String, bestFriend: String) {
        print("Enrolling \(name) in class…")
        self.name = name
        self.bestFriend = bestFriend
    }
}

You don’t have to use that, of course, but it gets a little clumsy adding some sort of prefix to the parameter names:

struct Student {
    var name: String
    var bestFriend: String

    init(name studentName: String, bestFriend studentBestFriend: String) {
        print("Enrolling \(studentName) in class…")
        name = studentName
        bestFriend = studentBestFriend
    }
}

Outside of initializers, the main reason for using self is because we’re in a closure and Swift requires us to so we’re making it clear we understand what’s happening. From Swift 5.3 or later this situation has greatly improved, meaning that self won’t be needed so much in regular methods.

Hacking with Swift is sponsored by NSSpain

SPONSORED Announcing NSSpain 2020: Remote Edition! An online, continuous conference for iOS developers. We’ll start on Thursday and finish on Friday, with talks, activities, and lots of fun for 36 hours, non-stop. Sound good? Join us!

Find out more

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!

Link copied to your pasteboard.