Trying to avoid repeating elements on list (random.range)

Questions & Answers
1

This is a bit of a followup to this post: https://answers.unity.com/questions/1709250/transformrotate-on-z-axis-moves-the-entire-object.html?childToView=1709334#comment-1709334

I have a circle of 4 colors, and the player gets one of these colors randomly when it collides with a certain object.

What I’m trying to do is to make sure that the player doesn’t pick the same color twice in a row. I tried clearing the list of colors and then resetting it by adding a copy of the original list to the list, like so:

public class Player : MonoBehaviour
{
    public float jumpForce = 10f;
    public string currentColor;

    public List<Color> colors;
    public List<Color> copy;

    Rigidbody2D rb;
    SpriteRenderer sr;

    void Start()
    {
        rb = GetComponent<Rigidbody2D>();
        sr = GetComponent<SpriteRenderer>();

        SetRandomColor();
    }

    void Update()
    {
        if(Input.GetButtonDown("Jump") || Input.GetMouseButtonDown(0))
        {
            rb.velocity = Vector2.up * jumpForce;
        }
    }

    private void OnTriggerEnter2D(Collider2D col)
    {
        if(col.tag == "ColorChanger")
        {
            SetRandomColor();
            Destroy(col.gameObject);
            return;
        }

        if(col.tag != currentColor || col.tag == "Border")
        {
            Debug.Log("GAME OVER!");
            SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
        }
    }

    void SetRandomColor()
    {
        int index = Random.Range(0, colors.Count);

        switch(index)
        {
            case 0:
                currentColor = "Cyan";
                sr.color = colors[0];
                colors.RemoveAt(0);
                break;
            case 1:
                currentColor = "Yellow";
                sr.color = colors[1];
                colors.RemoveAt(1);
                break;
            case 2:
                currentColor = "Purple";
                sr.color = colors[2];
                colors.RemoveAt(2);
                break;
            case 3:
                currentColor = "Pink";
                sr.color = colors[3];
                colors.RemoveAt(3);
                break;
        }

        ResetColorList();
    }

    void ResetColorList()
    {
        if(!colors.Any<Color>())
        {
            Debug.Log("List is empty");
            colors.AddRange(copy);
        }
    }
}

This is what the player looks like:

154592-editor.png
154592-editor.png1920×1080 134 KB

The player does change color, and everything else in the code works , but I don’t know how to avoid the repeating numbers in the list. Any help would be appreciated.

2

You could use a third temporary list to randomize the colors, like so:

        List<Color> temp = colors;

        while ( temp.Count > 0 )
        {
            int randomNumber = UnityEngine.Random.Range( 0 , temp.Count );
            copy.Add( temp[ randomNumber ] );
            temp.RemoveAt( randomNumber );
        }

This way there is a very small chance you could still get the same exact order.