How do you Iterate a multidimesional array without knowing the number of dimensions and elements of the array being passed to you?

Question

A SDK is returning me an array with multiple dimensions such as:

int[,,] theArray = new int[2,8,12];

I need to visit each element in the array and return the value and the position of the value. I need to do this without knowing the number of dimensions and elements of the array being passed in.

Answer 1

Would something like this work for you? It recurses the ranks so you can use a foreach() and get an array containing the current item's indices.

class Program
{
    static void Main(string[] args)
    {
        int[, ,] theArray = new int[2, 8, 12];
        theArray[0, 0, 1] = 99;
        theArray[0, 1, 0] = 199;
        theArray[1, 0, 0] = 299;

        Walker w = new Walker(theArray);

        foreach (int i in w)
        {
            Console.WriteLine("Item[{0},{1},{2}] = {3}", w.Pos[0], w.Pos[1], w.Pos[2], i);
        }

        Console.ReadKey();
    }

    public class Walker : IEnumerable<int>
    {
        public Array Data { get; private set; }
        public int[] Pos { get; private set; }

        public Walker(Array array)
        {
            this.Data = array;
            this.Pos = new int[array.Rank];
        }

        public IEnumerator<int> GetEnumerator()
        {
            return this.RecurseRank(0);
        }

        private IEnumerator<int> RecurseRank(int rank)
        {
            for (int i = this.Data.GetLowerBound(rank); i <= this.Data.GetUpperBound(rank); ++i)
            {
                this.Pos.SetValue(i, rank);

                if (rank < this.Pos.Length - 1)
                {
                    IEnumerator<int> e = this.RecurseRank(rank + 1);
                    while (e.MoveNext())
                    {
                        yield return e.Current;
                    }
                }
                else
                {
                    yield return (int)this.Data.GetValue(this.Pos);
                }
            }
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return this.RecurseRank(0);
        }
    }
}

Answer 2

Use for loops:

for (int i=theArray.GetLowerBound(0);i<=theArray.GetUpperBound(0);++i)
{
    for (int j=theArray.GetLowerBound(1);j<=theArray.GetUpperBound(1);++j)
    {
        for (int k=theArray.GetLowerBound(2);k<=theArray.GetUpperBound(2);++k)
        {
           // do work, using index theArray[i,j,k]
        }
    }
}

If you don't know the number of dimensions in advance, you can use Array.Rank to determine that.

Answer 3

I'm not sure I understand your question about "return the position[n,n,n]", but if you're trying to return more than one value from a method, there are a couple of ways to do it.

• Useoutor reference parameters (e.g.,Int) that get set to the returned values before returning from the method.

• Pass in an array, e.g., an array of three ints, the elements of which get set by the method before it returns.

• Return an array of values, e.g., an array of three ints.