Question

I want write extension method for fill multidimensional rectangular array. I know how to do it for the array with a fixed number of measurements:

public static void Fill<T>(this T[] source, T value)
{
    for (int i = 0; i < source.Length; i++)
        source[i] = value;
}
public static void Fill<T>(this T[,] source, T value)
{
    for (int i = 0; i < source.GetLength(0); i++)
        for (int j = 0; j < source.GetLength(1); j++)
            source[i, j] = value;
}
public static void Fill<T>(this T[,,] source, T value)
{
    for (int i = 0; i < source.GetLength(0); i++)
        for (int j = 0; j < source.GetLength(1); j++)
            for (int k = 0; k < source.GetLength(2); k++)
                source[i, j, k] = value;
}

Can I write one fill-method for all multidimensional rectangular array?

Answer 1

You can change the fixed dimension parameter to an Array parameter so you can put the extension on any Array. Then I used recursion to iterate through each position of the array.

public static void Fill<T>(this Array source, T value)
{
    Fill(0, source, new long[source.Rank], value);
}

static void Fill<T>(int dimension, Array array, long[] indexes, T value)
{
    var lowerBound = array.GetLowerBound(dimension);
    var upperBound = array.GetUpperBound(dimension);
    for (int i = lowerBound; i <= upperBound; i++)
    {
        indexes[dimension] = i;
        if (dimension < array.Rank - 1)
        {
            Fill(dimension + 1, array, indexes, value);
        }
        else
        {
            array.SetValue(value, indexes);
        }
    }
}