Convert from BitArray to Byte

Question

I have a BitArray with the length of 8, and I need a function to convert it to a byte. How to do it?

Specifically, I need a correct function of Co

Answer 1

Unfortunately, the BitArray class is partially implemented in .Net Core class (UWP). For example BitArray class is unable to call the CopyTo() and Count() methods. I wrote this extension to fill the gap:

public static IEnumerable<byte> ToBytes(this BitArray bits, bool MSB = false)
{
    int bitCount = 7;
    int outByte = 0;

    foreach (bool bitValue in bits)
    {
        if (bitValue)
            outByte |= MSB ? 1 << bitCount : 1 << (7 - bitCount);
        if (bitCount == 0)
        {
            yield return (byte) outByte;
            bitCount = 8;
            outByte = 0;
        }
        bitCount--;
    }
    // Last partially decoded byte
    if (bitCount < 7)
        yield return (byte) outByte;
}

The method decodes the BitArray to a byte array using LSB (Less Significant Byte) logic. This is the same logic used by the BitArray class. Calling the method with the MSB parameter set on true will produce a MSB decoded byte sequence. In this case, remember that you maybe also need to reverse the final output byte collection.

Answer 2

This should work:

byte ConvertToByte(BitArray bits)
{
    if (bits.Count != 8)
    {
        throw new ArgumentException("bits");
    }
    byte[] bytes = new byte[1];
    bits.CopyTo(bytes, 0);
    return bytes[0];
}

Answer 3

That's should be the ultimate one. Works with any length of array.

private List<byte> BoolList2ByteList(List<bool> values)
    {

        List<byte> ret = new List<byte>();
        int count = 0;
        byte currentByte = 0;

        foreach (bool b in values) 
        {

            if (b) currentByte |= (byte)(1 << count);
            count++;
            if (count == 7) { ret.Add(currentByte); currentByte = 0; count = 0; };              

        }

        if (count < 7) ret.Add(currentByte);

        return ret;

    }