I have a function that returns index of an 2d array like this
public int[] getIndex()
{
return new int[2] { i, j };
}
I want to be able to use this function to directly access the value of the 2d array, so for example
var val = array[getIndex()]
But the getIndex() throws an error. Is there any other way I can return a key for a 2d array? or do I have to manually specify
var val = array[getIndex()[0], getIndex()[1]]
You can use Array.GetValue():
int element = (int)array.GetValue(getIndex());
Note that this needs a cast. I have used int in this example, but you would need to use the correct type for your array.
If you don't like having to cast, you could write an extension method:
public static class Array2DExt
{
public static T At<T>(this T[,] array, int[] index)
{
return (T) array.GetValue(index);
}
}
Which you would call like this:
var element = array.At(getIndex());
If you left with your solution manually specifying the indexes I suggest to use the code below instead. Assuming you getIndex() does more than returning some internal variables this code will perform better.
var requiredItemIndex = getIndex();
var val = array[requiredItemIndex[0], requiredItemIndex[1]];
I would consider creating a custom 2D array instead, and use a value tuple or a custom point-type to describe the index. For example:
public class My2DArray<T>{
public int Width { get; }
public int Height { get; }
public T[] Data { get; }
public My2DArray(int width, int height)
{
Width = width;
Height = height;
Data = new T[width * height];
}
public T this[int x, int y]
{
get => Data[y * Width + x];
set => Data[y * Width + x] = value;
}
public T this[(int x, int y) index]
{
get => Data[index.y * Width + index.x];
set => Data[index.y * Width + index.x] = value;
}
}
An advantage with this approach is that you can directly access the backing array. So if you just want to process all items, without caring about their location, you can just use a plain loop.
