How do I convert an array of floats to a byte[] and back?

halfbit picture halfbit · Jan 8, 2011 · Viewed 61.4k times · Source

I have an array of Floats that need to be converted to a byte array and back to a float[]... can anyone help me do this correctly?

I'm working with the bitConverter class and found myself stuck trying to append the results.

The reason I'm doing this is so I can save runtime values into a IO Stream. The target storage is Azure Page blobs in case that matters. I don't care about what endian this is stored in, as long as it input matches the output.

static  byte[] ConvertFloatToByteArray(float[] floats)
        {
            byte[] ret = new byte[floats.Length * 4];// a single float is 4 bytes/32 bits

            for (int i = 0; i < floats.Length; i++)
            {
               // todo: stuck...I need to append the results to an offset of ret
                ret = BitConverter.GetBytes(floats[i]);

            }
            return ret;
        }


 static  float[] ConvertByteArrayToFloat(byte[] bytes)
{ //to do }

Answer

LukeH picture LukeH · Jan 9, 2011

If you're looking for performance then you could use Buffer.BlockCopy. Nice and simple, and probably about as fast as you'll get in managed code.

var floatArray1 = new float[] { 123.45f, 123f, 45f, 1.2f, 34.5f };

// create a byte array and copy the floats into it...
var byteArray = new byte[floatArray1.Length * 4];
Buffer.BlockCopy(floatArray1, 0, byteArray, 0, byteArray.Length);

// create a second float array and copy the bytes into it...
var floatArray2 = new float[byteArray.Length / 4];
Buffer.BlockCopy(byteArray, 0, floatArray2, 0, byteArray.Length);

// do we have the same sequence of floats that we started with?
Console.WriteLine(floatArray1.SequenceEqual(floatArray2));    // True