How to create a 1-Dimensional Array in C# with index starting at 1

Question

For multidimensional arrays Array.CreateInstance can be used to create non-zero index based arrays, but if you try that for a 1-dimensional arrays (vectors) as in e.g.:

Answer 1

You can make a non-zero-based array in C#, but the useage of it is kind-of obnoxious. It is definitly not a simple substitute for a normal (i.e., zero-based single dimentional) array.

        // Create the array.
        Array myArray = Array.CreateInstance(typeof(double), new int[1] { 12 }, new int[1] { 1 });

        // Fill the array with random values.
        Random rand = new Random();
        for (int index = myArray.GetLowerBound(0); index <= myArray.GetUpperBound(0); index++)
        {
            myArray.SetValue(rand.NextDouble(), index);
        }

        // Display the values.
        for (int index = myArray.GetLowerBound(0); index <= myArray.GetUpperBound(0); index++)
        {
            Console.WriteLine("myArray[{0}] = {1}", index, myArray.GetValue(index));
        }

The GetValue/SetValue syntax that is required for this is uglier than subtracting one from a vector index at each occurance.

If a value type is stored in the array, then it will be stored in consecutive position just as in a regular array, but the getter and setter will require boxing of the values (unless there is some compiler magic that I am not aware of). And the getter will usually require a cast (just to make it even uglier).

    double myValue = (double)myArray.GetValue(index);

Also note that the correct comparison for GetUpperBound is <=, unlike Length which is compared with <.