A so-called “fair” random number generator is one that generates each of its possible values in equal amounts and with an even distribution. For example, if you were generating numbers between 1 and 4, you might get 4, 2, 1, 3, but you would never get 4 4 1 4.
GameplayKit has support for fair random number generation using
GKShuffledDistribution. First, add an import for the GameplayKit framework:
Second, create an instance of
GKShuffledDistribution, telling it the lowest and highest values it can generate:
let distribution = GKShuffledDistribution(lowestValue: 1, highestValue: 8)
nextInt() on it as needed to generate numbers. You should get all numbers between 1 and 8 at least once before you see any repeated.
Sponsored You’re already busy updating your app for Swift 4.2 and iOS 12, so why not let Instabug help you find and fix bugs? Add just two lines of code to your project and receive comprehensive reports with all the feedback you need to ship a world-class app – click here to learn more!
Available from iOS 9.0 – see Hacking with Swift tutorial 35
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Build for watchOS
Take your existing Swift skills to Apple's tiniest platform – check out Hacking with watchOS!