Tuples Swift

What are tuples ?

Tuples group multiple values into a single compound value. The values within a tuple can be of any type and don’t have to be of the same type as each other.

Here we are going to see about the various types of Tuples structuring, dismantle (decompose) and tuple comparison. Naming or positioning are the key for any tuple.

Structuring

Tuples can be created/structured using the below ways

Option 1: Simple Comma “,”

Simple grouping separated with commas “,”

let http404Error = (404, “Not Found”)

Option 2: Naming elements

Naming the individual elements

let http200Status = (statusCode: 200, description: “OK”)

Decomposing

As like structuring there are couple of ways to access the tuple elements,

Options 1: Using Index

Access the individual element values in a tuple using index numbers starting at zero

let http404Error = (404, “Not Found”)

let code = http404Error.0

let message = http404Error.1

Option 2: Element name

Using element names to access the elements

let http200Status = (statusCode: 200, description: “OK”)

let code = http200Status.statusCode

let message = http200Status.description

Option 3: Value binding

let http404Error = (404, “Not Found”)

let (justTheStatusCode, _ ) = http404Error

justTheStatusCode is now 404. Parts of the tuple with an underscore (_) is ignored.

Comparison

You have two golden rules to compare tuple

1. Tuples are compared from left to right, one value at a time, until the comparison finds two values that aren’t equal.

2. If all the elements are equal, then the tuples themselves are equal

Those two values are compared, and the result of that comparison determines the overall result of the tuple comparison. . For example

1. (1, “zebra”) < (2, “apple”) // true because 1 is less than 2; “zebra” and “apple” are not compared — Rule 1, 1 and 2 are unequal and 1 < 2 is true
2. (3, “apple”) < (3, “bird”) // true because 3 is equal to 3, and “apple” is less than “bird” — Rule 1, because 3 is equal to 3 it goes to the next value until the comparison finds two values that aren’t equal i.e checks “apple” and “bird” where “apple” < “bird” is true
3. (4, “dog”) == (4, “dog”) // true because 4 is equal to 4, and “dog” is equal to “dog” — Rule 2

Fact: Swift can compare only upto seven values in a tuple

Reference

The Basics - The Swift Programming Language (Swift 5.3)