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How to generate a random number with GKRandomSource

Swift version: 5.0

Paul Hudson    @twostraws   

GameplayKit is a powerful new framework introduced in iOS 9.0, and one of the (many!) things it does is provide a number of ways to generate random numbers easily. To get started, import the framework into your code like this:

import GameplayKit

You can immediately start generating random numbers just by using this code:

print(GKRandomSource.sharedRandom().nextInt())

That code produces a number between -2,147,483,648 and 2,147,483,647, so if you're happy with negative numbers then you're basically done. Alternatively, if you want a random number between and an upper bound (inclusive!), you should use this code instead:

print(GKRandomSource.sharedRandom().nextInt(upperBound: 10))

That will return a number between 0 and 10, including 0 and 10 themselves.

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Available from iOS 9.0 – see Hacking with Swift tutorial 35

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