Mapping a multidimensional array

Question

I have the following class

class Tile
{
    public int height;
    public int terrain;
}

And I have a 2D array of Tiles

Tile[,] area = new Tile[5,5];

How could I map my area from a Tile[,] to a int[,], where only the height is saved?

I tried doing this:

area.Select(tile => tile.height)

but apparently C# Multidimensional arrays do not implement IEnumerable.

How could I solve this problem?

Answer 1

How could I solve this problem?

By writing code. There's no "select" that works, so make your own:

static class Extensions 
{
  public static R[,] Select<T, R>(this T[,] items, Func<T, R> f) 
  {
    int d0 = items.GetLength(0);
    int d1 = items.GetLength(1);
    R[,] result = new R[d0, d1];
    for (int i0 = 0; i0 < d0; i0 += 1)
      for (int i1 = 0; i1 < d1; i1 += 1)
        result[i0, i1] = f(items[i0, i1]);
    return result;
  } 
}

And now you have the extension method you want.

EXERCISES:

• Which of the standard LINQ sequence operators make sense to adapt to multidimensional arrays, and which do not?
• Are there operators you'd like to see on multidimensional arrays that are not standard LINQ operators but which you could implement as extension methods?