How to generate non-repeating Random Numbers in Unity - unity3d

Question

I am trying to create a simple Bingo game and want to make sure the numbers are not repeating on the bingo card. I have a random number generator, but for some reason the code I'm using doesn't work as the same numbers will constantly repeat. Could somebody please take a look at my code below and either tell me what I need to fix or fix the code for me?
public Grid(int width, int height, float cellSize)
{
this.width = width;
this.height = height;
this.cellSize = cellSize;
gridArray = new int[width, height];
debugTextArray = new TextMesh[width, height];
for (int x = 0; x < gridArray.GetLength(0); x++)
{
for (int y = 0; y < gridArray.GetLength(1); y++)
{
debugTextArray[x, y] = UtilsClass.CreateWorldText(gridArray[x, y].ToString(), null, GetWorldPosition(x, y) + new Vector3(cellSize, cellSize) * .5f, 20, Color.white, TextAnchor.MiddleCenter);
Debug.DrawLine(GetWorldPosition(x, y), GetWorldPosition(x, y + 1), Color.white, 100f);
Debug.DrawLine(GetWorldPosition(x, y), GetWorldPosition(x + 1, y), Color.white, 100f);
}
}
Debug.DrawLine(GetWorldPosition(0, height), GetWorldPosition(width, height), Color.white, 100f);
Debug.DrawLine(GetWorldPosition(width, 0), GetWorldPosition(width, height), Color.white, 100f);
for (int x = 0; x <= 4; x++)
{
RandomValue(0, x);
RandomValue(1, x);
RandomValue(2, x);
RandomValue(3, x);
RandomValue(4, x);
}
}
private Vector3 GetWorldPosition(int x, int y)
{
return new Vector3(x, y) * cellSize;
}
public void RandomValue(int x, int y)
{
if (x >= 0 && y >= 0 && x < width && y < height)
{
list = new List<int>(new int[Lenght]);
for (int j = 0; j < 25; j++)
{
Rand = UnityEngine.Random.Range(1, 50);
while (list.Contains(Rand))
{
Rand = UnityEngine.Random.Range(1, 50);
}
list[j] = Rand;
gridArray[x, y] = list[j];
}
debugTextArray[x, y].text = gridArray[x, y].ToString();
debugTextArray[2, 2].text = "Free";
}
}

Answer 1

Basically your concept in function RandomValue() is correct, but problem is it only check in same column, so you have to bring the concept of RandomValue() to Grid() level. You need a List contain all approved value, then check Contains() at Grid().
But in fact you can do it in all one go.
Make sure your width*height not larger than maxValue.
Dictionary<Vector2Int, int> CreateBingoGrid(int width, int height, int maxValue)
{
var grid = new Dictionary<Vector2Int, int>();
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
var num = Random.Range(1, maxValue);
while (grid.ContainsValue(num))
{
num = Random.Range(1, maxValue);
}
grid.Add(new Vector2Int(x, y), num);
}
}
return grid;
}

Answer 2

As mentioned in the comment on your question, it's probably the easiest to just shuffle the numbers in the range [1,50] and then take the first 25 or however many you want.
The reason your code isn't working properly and you see a lot of repeats is because you're calling the RandomValue() function multiple separate times and the list variable you're comparing against if a value is already on the chart is inside of that function. Meaning that it will only ever check the values it has generated in that call, in this case meaning only for one row.
Also, if you make a list that you know will always be the same size, you should use an array instead. Lists are for when you want the size to be adjustable.
Solution 1:
A very simple way to generate an array with the numbers 1-50 would be to do this:
//Initialize Array
int[] numbers = new int[50];
for (int i = 1; i <= numbers.Length; i++)
{
numbers[i] = i;
}
//Shuffle Array
for (int i = 0; i < numbers.Length; i++ )
{
int tmp = numbers[i];
int r = Random.Range(i, numbers.Length);
numbers[i] = numbers[r];
numbers[r] = tmp;
}
//Get first 'n' numbers
int[] result = Array.Copy(numbers, 0, result, 0, n);
return result;
I'm not sure if it's the most efficient way, but it would work.
Solution 2:
To change your code to check against the entire list, I would change this section:
for (int x = 0; x <= 4; x++)
{
RandomValue(0, x);
RandomValue(1, x);
RandomValue(2, x);
RandomValue(3, x);
RandomValue(4, x);
}
To something like this:
List<int> values = new List<int>();
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
int r = RandomValue(1, 50);
while (values.Contains(r))
{
r = RandomValue(1, 50);
}
values[y * width + x].Add(r);
gridArray[x, y] = r;
}
}
int RandomValue(int min, int max) {
return UnityEngine.Random.Range(min, max);
}
Hope this helps!