Swift Tuples

Jun 6, 2021

Learn how to use tuples in Swift to group several values together, name and decompose their elements, return multiple values, and even swap variables.

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This tutorial belongs to the Swift series

Tuples are used to group multiple values into a single collection. For example we can declare a variable dog containing a String and an Int value:

let dog : (String, Int)

And we can initialize them with a name and an age

let dog : (String, Int) = ("Roger", 8)

But as with any other variable, the type can be inferred during initialization:

let dog = ("Roger", 8)

You can use named elements:

let dog = (name: "Roger", age: 8)

dog.name //"Roger"
dog.age //8

Once a tuple is defined, you can decompose it to individual variables in this way:

let dog = ("Roger", 8)
let (name, age) = dog

and if you need to just get one of the values, you can use the special underscore keyword to ignore the other ones:

let dog = ("Roger", 8)
let (name, _) = dog

Tuples are an awesome tool for various needs.

The most obvious one is a short way to group similar data.

Another one if those needs is returning multiple items from a function. A function can only return a single item, so a tuple is a convenient structure for that.

Another handy functionality allowed by tuples is swapping elements:

var a = 1
var b = 2

(a, b) = (b, a)

//a == 2
//b == 1

Tagged: Swift · All topics

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