Converting an int[] to byte[] in C#

I know how to do this the long way: by creating a byte array of the necessary size and using a for-loop to cast every element from the int array.

I was wondering if there was a faster way, as it seems that the method above would break if the int was bigger than an sbyte.

Solution 1:

If you want a bitwise copy, i.e. get 4 bytes out of one int, then use Buffer.BlockCopy:

byte[] result = new byte[intArray.Length * sizeof(int)];
Buffer.BlockCopy(intArray, 0, result, 0, result.Length);

Don't use Array.Copy, because it will try to convert and not just copy. See the remarks on the MSDN page for more info.

Besides the accepted answer (which I am now using), an alternative one-liner for Linq lovers would be:

byte[] bytes = ints.SelectMany(BitConverter.GetBytes).ToArray();

I suppose, though, that it would be slower...