Declaring and Initializing 2D arrays in C#

Unity Engine
1

Can anyone tell me what’s the best way to initialize a 2D array of vectors in C#??

This is what I tried to do:

private Vector3[][] spawnGrid;


spawnGrid[0][0] = new Vector3(-2.5f, 0f, 1.5f);
        spawnGrid[0][1] = new Vector3(-2.5f, 0f, 0.5f);
        spawnGrid[0][2] = new Vector3(-2.5f, 0f, -1.5f);
        spawnGrid[0][3] = new Vector3(-2.5f, 0f, -2.5f);

        spawnGrid[1][0] = new Vector3(-1.5f, 0f, 1.5f);
        spawnGrid[1][1] = new Vector3(-1.5f, 0f, 0.5f);
        spawnGrid[1][2] = new Vector3(-1.5f, 0f, -1.5f);
        spawnGrid[1][3] = new Vector3(-1.5f, 0f, -2.5f);

        spawnGrid[2][0] = new Vector3(0.5f, 0f, 1.5f);
        spawnGrid[2][1] = new Vector3(0.5f, 0f, 0.5f);
        spawnGrid[2][2] = new Vector3(0.5f, 0f, -1.5f);
        spawnGrid[2][3] = new Vector3(0.5f, 0f, -2.5f);

I dont get any syntax error but I get a NullReferenceException at the point where I access an element of this array like so:

GameObject GO;
            GO = (GameObject)Instantiate(enemies[0], spawnGrid[0][0], transform.rotation);

Does anyone see the problem here?

Please help!

2

You haven’t initialized any of the arrays. In any case, that’s the syntax for a jagged array; seems like you want a 2D array.

private Vector3[,] spawnGrid = new Vector3[3, 4];

–Eric

2 Likes
3

Thanks for replying. But this time, I am getting a new error like such:

error CS0022: Wrong number of indexes `1' inside [], expected `2' at the point I am accessing an element.

Do you see the problem here?

Thanks!

4

If you intialize the array as eric proposed, you need to access elements like this:

spawnGrid[0,0] = new Vector3(-2.5f, 0f, 1.5f);
5

Thanks a lot guys…I am not familiar with a lot of syntax in C# and I am still very new to this language. But thanks to you guys to make my life easier!

6

You are probably done with this coding already, but you can make it even simpler just by doing this:

  • private Vector3[,] spawnGrid = new Vector3[3, 4];
    • void SpawnGrid()
  • {
  • for (int i = 0; i < 3; i++)
  • {
  • for (int j = 0; j < 4; j++)
  • {
  • spawnGrid[i, j] = new Vector3(x, 0f, z);
  • z -= 1;
  • }
    • x += 1;
  • z = 1.5f; //gives original value back to Z.
  • }
  • }
1 Like