How does one generate a random number in Apple’s Swift language?

Use the standard library functions for high quality random numbers: arc4random() or arc4random_uniform(), just as in Objective-C.

They are in the Darwin module, so if you haven't imported AppKit, UIKit, or Foundation (which import it for you), you will need to import Darwin.

Swift 4.2

Swift 4.2 shipped with Xcode 10 introduces new easy-to-use random functions for many data types. You can call the random() method on numeric types.

let randomInt = Int.random(in: 0..<6)
let randomDouble = Double.random(in: 2.71828...3.14159)
let randomBool = Bool.random()