Generate a unique random number between 1 and 10?

Question

I want to generate a unique random digit between 1 and 10. If a number gets repeated then the script should skip the number and try for another. If there are no unique numbers left then a message should be generated. Any logic to get this concept implemented?

public int number; 

    void Update () {
        if(Input.GetKeyDown(KeyCode.A))
        {
          number= Random.Range(1,10);
        }
    }

EDIT: It is not a duplicate of the link the user posted since I am trying to generate unique number and if a particular number is repeated, the script ignores it and tries to look for another number.

Possible duplicate of [Randomize a List](https://stackoverflow.com/questions/273313/randomize-a-listt) — Silvermind, Jul 09 '19 at 08:58
Create a collection of `1..10` values, *shuffle* it, then take `1st, 2nd, ..., 10th` item from it when all items are taken generate the message — Dmitry Bychenko, Jul 09 '19 at 08:59
Possible duplicate of [Generating random, unique values C#](https://stackoverflow.com/questions/14473321/generating-random-unique-values-c-sharp) — Owen Pauling, Jul 09 '19 at 09:09
Probably not a duplicate. Very very similar, but Unity Random acts differently than System Random. — Jack Mariani, Jul 09 '19 at 09:33

Jack Mariani · Accepted Answer · 2019-07-09T12:54:53.310

Setup a list with all the valid values at Awake
Get a random value from the list
Remove the value from the list to avoid duplicates
BONUS - You could also extend the class to set any min and max numbers

public class RandomGenerator : MonoBehaviour
{
    public int minNumber = 1;
    public int maxNumber = 10;

    private List<int> _validNumbers;

    public int number;

    private void Awake()
    {
        _validNumbers = new List<int>();
        for (int i = minNumber; i <= maxNumber; i++)
            _validNumbers.Add(i);
    }

    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.A))
        {
            if (_validNumbers.Count == 0)
                Debug.Log("No valid Numbers");
            else
                number = GetRandomNumber();
        }
    }

    private int GetRandomNumber()
    {
        var nextIndex = Random.Range(0, _validNumbers.Count - 1);
        var result    = _validNumbers[nextIndex];
        _validNumbers.RemoveAt(nextIndex);
        return result;
    }
}

EDIT AFTER COMMENTS:
This question is very similar to this other question. But Unity.Random is different than System.Random.

The answers offered in the other question work here too. But we have more choices here.

Seems like you linked the "this other question" to this one. — Everts, Jul 09 '19 at 12:36
Thanks for the comment. Just updated the link: https://stackoverflow.com/questions/14473321/generating-random-unique-values-c-sharp — Jack Mariani, Jul 09 '19 at 12:37

Johnny · Answer 2 · 2019-07-09T20:37:29.360

As guys suggested in the comments, shuffling might work:

public class Shuffler
{
    private readonly Queue<int> _queue;

    public Shuffler(int max)
    {           
        _queue = new Queue<int>(Enumerable.Range(1, max).OrderBy(x => UnityEngine.Random.value));
    }

    public bool TryGetNext(out int item)
    {
        if(_queue.Count == 0)
        {
            item = -1;
            return false;
        }

        item = _queue.Dequeue();
        return true;
    }
}

For the sake of completenes, adding MonoBehaviour, e.g.

public class RandomNumber : MonoBehaviour
{
    private Shuffler _shuffler;

    public int number;

    private void Awake()
    {
        _shuffler = new Shuffler(10)
    }

    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.A))
        {
            if(!_shuffler.TryGetNext(out number))
            {
                Debug.Log("No valid Numbers");
            }
        }
    }
}

Generate a unique random number between 1 and 10?

2 Answers2