How to generate unique random number

Question

hi , i am new in unity , but i work at IOS cocos2d and sprite-kit. i made unique random number at cocos2d the code are given below , but i just cant make that thing convert properly at unity

here is the code at objective c

 -(void)CreateRandomCircle{
     int Range = 20;
     int random;
     
     int checker[Range];
     for(int i = 0 ; i < Range ; i++)
     {
         checker[i] = 0;
     }
     for(int i = 0 ; i < Range ; i++)
         
     {
         random = arc4random() % Range;
         
         while(checker[random] == 1)
             
         {
             random = arc4random() % Range;
         }
         checker[random] = 1;
         
         NumArray2 [i]=random;
     }
 }

but i tried to make it in unity here is my try

 private int randomm;
 
     private int[] checker = new int[];
     private int[] UnicNumArray = new int[20];

 
     void CreateRandomCircle()
     {
         checker = new int[20];
         for (int i = 0; i <20 ; i++)
         {
                 checker [i] = 0;
             randomm = Random.Range (0, 20);
             print(randomm);
 
             while (checker[randomm] == 1) 
             {
                 randomm = Random.Range (0, 3);
             }
             checker [randomm] = 1;
             UnicNumArray [i] = randomm;
         }
     }

please this will be a big time help .

again all i want is 20 unique random number at one single array

Answer 1

Best Answer

Answer by Anxo · May 27, 2014 at 02:56 PM

Something like this? I have not tested it but this should give you a list of int from 0 to 19 in a random order. If I understood your question correctly.

 using System.Collections.Generic

 private int maxNum = 20;
 private List <int> randomList;
 
 
 public void GenerateRandomList (){
     for(int i = 0; i < maxNum; i++){
        int numToAdd = Random.Range(0,maxNum);
        while(!randomList.contains(numToAdd)){
           numToAdd = Random.Range(0,maxNum);
        }
        randomList.Add(numToAdd);
 
    }
    //Done. 
 }

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Anxo · May 27, 2014 at 03:06 PM 0

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Oh do not forget

 void Start(){
    randomList = new List<int> ();
 }

And a cleaner version might actually be something like this instead.

 private int maxNumbers = 20;
 private List<int> uniqueNumbers;
 private List<int> finishedList;
 
 void Start(){
    uniqueNumber = new List<int>();
    finishedList = new List<int>();
 }
 
 public void GenerateRandomList(){
    for(int i = 0; i < maxNumbers; i++){
       uniqueNumbers.Add(i);
    }
    for(int i = 0; i< maxNumbers; i ++){
      int ranNum = uniqueNumbers[Random.Range(0,uniqueNumbers.Count)];
      finishedNumbers.Add(ranNum);
      uniqueNumbers.Remove(ranNum)
    } 
    //Done.
 }

I think this is cleaner b/c it leaves less things to chance.

tuhin_09 · May 27, 2014 at 05:01 PM 0

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thank you.........its works........thnx a lot

TKS_Keeper · May 27, 2014 at 05:30 PM 0

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Remember to accept the answer if it worked.

nur farazi · May 28, 2014 at 05:03 PM 0

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i was having the same problem , thank you

BlasterJoker · Nov 20, 2014 at 03:04 AM 0

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for the first solution, line 10 is not suppose to have the "!" symbol right? because we want to gen a new number if it DOES contain it.

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How to generate unique random number

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