I'm needing to create a random bool value in my game, in Swift.
It's basically, if Yes (or 1), spawn one object, if No (or 0), spawn the other.
So far, looking at this question and a similar one on here, I found this:
let randomSequenceNumber = Int(arc4random_uniform(2))
Now it works, but it seems bias to 0 to me... like ridiculously bias...
This is how I'm then using the value:
if(randomSequenceNumber == 0) //spawn object A else //spawn object B
Is there a better way to implement this using a random bool value? That isn't bias to a certain value?
Update
Bit of an experiment to see how many 1
's vs 0
's were were generated in 10,000 calls:
func experiment() { var numbers: [Int] = [] var tester: Int = 0 var sum = 0 for i in 0...10000 { tester = Int(arc4random_uniform(2)) numbers.append(tester) print(i) } for number in numbers { sum += number } print("Total 1's: ", sum) } Test 1: Console Output: Total 1's: 4936 Test 2: Console Output: Total 1's: 4994 Test 3: Console Output: Total 1's: 4995
To generate a random number in Swift, use Int. random() function. Int. random() returns a number, that is randomly selected, in the given range.
Swift has three typical functions for random numbers: arc4random() returns a random number between zero and 232–1. arc4random_uniform(_:) returns a random number between zero and the first parameter, minus one. drand48() returns a random Double between 0.0 and 1.0.
Looks like Apple engineers are listening
let randomBool = Bool.random()
import Foundation func randomBool() -> Bool { return arc4random_uniform(2) == 0 } for i in 0...10 { print(randomBool()) }
for more advanced generator the theory is available here
for basic understanding of Bernoulli (or binomial) distribution check here
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