C# - How do I copy alternate elements from one byte array to another

[Vivekananda]

I have a byte array. I need to copy alternate elements 0,2nd,4th ,6th ,8th elements ......and so on from the source byte array to new destination array.

How do I do that in C#?

[Plater]

Use a for loop and make it count by 2?
Or use a regular for loop and only take the ones were loopiterator%2= =0 ?

[Vivekananda]

Thanks for the reply.

I'm doing that. But I'm getting error saying that "{"Value cannot be null.\r\nParame ter name: dest"}"

Code snippet:

abyteArray0 = abyteArray[0]; //source
byte[] NewArray = null; //dest

            for (int i = 0; i < abyteArray0.Length ; i++)
            {
                if ((i % 2 == 0))
                {
                    //NewArray[i] = abyteArray0[i];
                    Array.Copy(abyteArray0, i, NewArray, i, 1);
                }
                i = i + 1;

            }

[Curtis Rutland]

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[Plater]

Well, to address your error, you never set your desitnation array to an instance of an array, you leave it at null. You cannot use a null object as an instance.

Secondly however, your loop/copy logic is a bit flawed (which you will see when you are able to step through it)

To get a newarray of the correct size, consider this:
byte[] NewArray = new byte[(oldarray.Lengt h/2)+(oldarray.Le ngth%2)];

if source array had 5 elements (.Length=5) 0 1 2 3 4
You want 0 2 4, which is an array with 3 elements (.Length=3)
oldarray.Length/2 will be 2 and oldarry.Length% 2 =1, so 2+1=3, the number of elements you need.

[Vivekananda]

Thanks very much. Got it!