i create a random array ,how avoiding repeat same value

Scripting
1

Hi guys,

I have created an array which displays random instructions .
But it still has a chance to duplicate values.
Can you tell me which part is wrong yet. :face_with_spiral_eyes:

public function random_array(){
	var i:int;
	var j:int;
	var arr = new Array();
	arr.length = 79;
	
	for(i = 1;i<80;i++){
		var r:int;
			r = Random.Range(1,80);
		//	Debug.Log("Run1");
		for(j = 1; j < i;j++){
			if(arr[j] == r ){
				r = Random.Range(1,80);
			//	Debug.Log("Run2");
			}
		}
		arr[i] = r;
		Debug.Log("Random : "+r);
	}
}
2

knuth-fisher-yates shuffle

3

If array size equals possible number count, you can generate array of following numbers (1…80) and permutate it.
Otherwise create list with all possible numbers and random indices from it:

var possibleValues = new Array();
// TODO; insert all possible values into array

var array = new Array();
array.length = 79;

for(i = 1; i < 80; i++)
{
    var index = Random.Range(0, possibleValues.length);
    array[i] = possibleValues[index];
    possibleValues = possibleValues.splice(index, 1);
}
4

Link you to a post i made about random unique numbers:

http://forum.unity3d.com/threads/186268-Fill-array-with-random-integers?p=1273126&viewfull=1#post1273126

5

Thank you for your answer

I have solved the problem :grin:

6

Just to note that most of the solutions provided above apply only to the “tight” set. Meaning n random non-repeating numbers in a range of n numbers. They don’t allow gaps between numbers. If I need to generate a 100 random non-repeating numbers in a range from 1 to 10000 then looks like most of the solutions fail. Correct me if I’m wrong but the only solution that works involves HashSet?