Not repeat random number (Random.Range)

Question

Hello, how can I prevent from a same random number? thanks :)

Answer 1

Answer by karl_ · Jul 22, 2013 at 10:18 PM

You could store the used values in a list or array, then check against it before using the random value.

Ex:

 List<int> usedValues = new List<int>();
 public int UniqueRandomInt(int min, int max)
 {
     int val = Random.Range(min, max);
     while(usedValues.Contains(val))
     {
         val = Random.Range(min, max);
     }
     return val;
 }

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CCV334 · Jul 31, 2017 at 05:48 PM 0

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Sometimes I get repeating numbers

     void Update()
     {
         if (Input.Get$$anonymous$$eyDown($$anonymous$$eyCode.P))
         {
             for (int i = 0; i < 3; i++)
             {
                 Debug.Log(UniqueRandomInt(-5, 2));
             }
         }
     }

Answer 2

Answer by fafase · Mar 05, 2015 at 07:07 AM

In order to never get twice the same value, you need to first store them and remove as you get them:

 int [] array = new int[]{0,1,2,3,4,5,6};
 List<int>list = null;
 void Start(){
     list.AddRange(array);
 }

 int GetUniqueRandom(bool reloadEmptyList){
      if(list.Count == 0 ){
          if(reloadEmptyList){
              list.AddRange(array); 
          }
          else{
              return -1; // here is up to you 
         }
     }
    int rand = Random.Range(0, list.Count);
    int value = list[rand];
    list.RemoveAt(rand);
    return value;
 }

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glady · Aug 15, 2016 at 03:43 PM 0

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@fafase the code is working the only problem is my scene is still repeated. can you help me fix my code?

huulong · Nov 07, 2016 at 01:00 PM 0

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for a solution in finite time for a discrete space, and allowing reload.

Note that Random.Range is inclusive according to Unit API, so you should use list.Count - 1 (not verified myself).

If the array is small or you know that you will use most of the values in the array, a shuffle (creating an array with reorderer values at once) is also acceptable. The "reload" part would be done by shuffling the array again.

DurgeshV · May 12, 2017 at 09:43 AM 0

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what if last number in the list gets the same as first number in the next loaded list.....

Answer 3

Answer by Romejanic · Jan 16, 2015 at 10:53 AM

 private static int lastRandomNumber;
 
 public static int generateRandomNumber(int min, int max) {
 
     int result = Random.Range(min, max);
 
     if(result == lastRandomNumber) {
 
             return generateRandomNumber(min, max);
 
     }
      
     lastRandomNumber = result;
     return result;
 
 }

Hope this helped you, Romejanic

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Answer 4

Answer by fransh · Jul 22, 2013 at 10:17 PM

 var newRandomNummer : float;
 var lastRandomNumber : float;
 var min : float;
 var max : float;
 
 function MakeRandomNumber() {
 newRandomNummer = Random.Range(min,max);
     if(newRandomNummer != lastRandomNumber){
         print(newRandomNummer);
     }
     else{
     //retry!
     }    
 }

That could work.

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Giannis7312777 · Jul 23, 2013 at 07:52 AM 0

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I want to make a combat system in my mmorpg game. $$anonymous$$y problem is when I hit 2 or more enemys I get their life + dealed damage not in random locations but in the same locations so I can't see their life and the dealed damage.. any suggestions?

fafase · Mar 05, 2015 at 06:58 AM 0

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Wrong way of doing here.

Here, each round you have a probability of missed hit, for instance, if you have only 2 values, you have a 50% chance to enter an endless loop and stop your game until you get the right value.

Answer 5

Answer by Eydamson · Mar 05, 2015 at 07:03 AM

you could use recursive functuion try this

 float RandomNum(float lastRandNum)
     {
 
         float randNum = Random.Range(min, max);
         if (randNum == lastRandNum)
         {
             return RandomNUm(randNum);
         }
         else
         {
             return randNum;
         }
     }

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Owen-Reynolds · Aug 15, 2016 at 04:03 PM 0

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In anything except Lisp or $$anonymous$$L, we just turn tail recursion into a loop: while(randNum==lastRandNum).

Plus, the poor OP is so confused they can't even describe the problem. $$anonymous$$entioning recursion just seems cruel.

Not repeat random number (Random.Range)

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