How to concatenate strings to make one joined string

Swift version: 5.10

Swift offers three different ways of joining strings. The first is using the + operator to join two strings to make a third:

let string1 = "Hello, "
let string2 = "world"
let combined1 = string1 + string2

The second is user string interpolation to make a new string”

let combined2 = "\(string1) \(string2)"

The last is using the += operator to add and assign a string to an existing string:

var combined3 = "Goodbye, "
combined3 += "cruel world"

Available from iOS 8.0

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.