Control quantity of Bools generated using arc4random

Question

In my spritekit game, I spawn one of two enemies. The enemy to be spawned is decided on a random generated bool, using arc4random_uniform(2).

I'm trying to create a way of controlling the distribution. Basically, I don't want it to generate 3 1's (true's) in a row...

I figured the best way to do that would be to check each time somethings generated, and increment a count, and if it exceeds the count, change the generated bool to the opposite value.

I think I'm confusing myself a little though as I can't get it to work.

Is there a simple way to do this, or can my code be modified to get it working? Thanks.

var randomSequenceNumber = Int(arc4random_uniform(2)) == 0 ? true: false

    if randomSequenceNumber {
        seqCount = randomSequenceNumber
        obNum++
        print("Obstacle Count: ", obNum)
    }

    if obNum <= 3 {
        randomSequenceNumber = !seqCount
        obNum = 0
    }

(probably having a major brain fart)

Answer 1

I wanted to generate random bools in a sequence, but should the same bool value get generated more than 3 times in a row, it was changed to the opposite.

But at the same time, I didn't just want it to just alternate, like true false true false true false etc

So it could gerate true false true false true false, or true true false false true false true false false true false but never true true true true false true false true false false false false... etc

This meant I needed to store the values, compare them, change the value if the last x amount matched, and reset the stored values ready to compare next time around.

This is how I did it:

var randSeqArray: [Bool] = []                          //empty array for bools

In my function that generates bools:

    randSeqArray.append(randomBool)                    //add bool to array
    if randSeqArray.count == 2 {                       //if matches count
        if randSeqArray[0] == randSeqArray[1] {        //if elements match
            print("-------> last two bools matched!")
            randomBool = !randomBool                   //change bool to opposite
        }
        randSeqArray.removeAll(keepCapacity: true)     //empty array
        randSeqArray.append(randomBool)                //add bool back, ready to check next time
    }

Obviously, this code ensures the random bool alternates (for testing), but it can be adopted to allow a possibility of up to x matching bools in a row before it gets reset.

This is the above example that checks if the last 3 generated bools match, ensuring that you never get more than 2 of the same bools in a row:

    randSeqArray.append(randomBool)
    if randSeqArray.count == 3 {
        if randSeqArray[0] == randSeqArray[1] && randSeqArray[1] == randSeqArray[2] {
            print("-------> last three bools matched!")
            randomBool = !randomBool
        }
        randSeqArray.removeAll(keepCapacity: true)
        randSeqArray.append(randomBool)
    }