Generate a random number different to the last

Questions & Answers
1

Hi there,

I need to generate a random number in unity that will be different to the last generated random number.

I have the following code and this is how you would do it in something like flash.

function getUniqueRandomSectionNumber(){
	var tempSectionNum : int = Random.Range(0, totalSections);

	if(tempSectionNum == lastCreatedSectionNum){
		getUniqueRandomSectionNumber();
	} else {
		lastCreatedSectionName = tempSectionNum;
		return tempSectionNum;

	}
}

However in Unity I don’t seem to be able to run the function from inside itself. In order to try again on the random number.

Hope this makes sense and thanks for any help

Will

4

int rand = Random.Range(0,totalSections);
while(rand==RandyAnterior){
rand = Random.Range(0,totalSections);
}
RandyAnterior = rand;

5

I know its 2018 but people would still be stumbling upon this question. So, maybe this would be helpful for someone. I was trying to spawn enemy planes in Augmented Reality. I wanted them to be randomly spawned but at a distance. For example, if one plane is spawned at 0,0,0. I wanted the next plane to be spawned at 0+20 or 0-20 on the X-Axis. Like, the new plane should spawn at 20 or more points from the present spawned point in positive and negative direction. Going through the forum i came across a code and modified it and then came to this:

 void RandonDistanceAxis()
 {
     distanceX = Random.Range (-70, 70);
     while (distanceX <= tempx + 20 && distanceX >= tempx - 20 )
     {
         distanceX = Random.Range (-70, 70);
     }
     tempx = distanceX;
     distanceY = Random.Range (-10,10);
     distanceZ = Random.Range (60,90);
 }

While declaring the tempx variable, give it a value of something out of the Range. I used 71. And it worked perfectly fine. Hope this helps. Cheers.

2

You could have the code in a while loop that only ends when the last random number is not equal to the current one. e.g:

function getUniqueRandomSectionNumber(){
    var hasFoundUniqueRandomSelection : bool;
    var tempSectionNum : int;

    while (!hasFoundUniqueRandomSelection) {
       tempSectionNum  = Random.Range(0, totalSections);
       if(tempSectionNum != lastCreatedSectionNum){
           hasFoundUniqueRandomSelection = true;
           lastCreatedSectionName = tempSectionNum;
       }
    }
    return tempSectionNum;
}

Apologies if I’ve made any mistakes, not accustomed to working with javascript.

3

Sir/Ma’am, even I had the same problem before but I fixed it with an if-condition.

currentNumber = Random.Range (0, markers.Length);
			if (lastNumber != currentNumber) 
			{
				lastNumber = currentNumber;
			} else 
			{
				currentNumber = Random.Range (0, markers.Length);
				lastNumber = currentNumber;
			}