Transforming Bitarray into to list of power of 2's

Question

I am trying to conver Bitarray into an array of corresponding decimal values if the bit is 1. The code I write is below but i don't want to use for loop. Is there a way around to avoid loop?

int right = 15;
var b = new BitArray(new int[] { right });
var valueList = new List<int>();
for (int i = 0; i < rightList.Count; i++)
{
         if (b[i])
         {
             valueList.Add((int)Math.Pow(2, i));
          }
}

Answer 1

Try copying the bits into an integer array directly.

    static void Main(string[] args)
    {
        var ba = new BitArray(new int[] { 15 });
        var array = new int[ba.Length / (8*sizeof(int))];
        ba.CopyTo(array, 0);
        Console.WriteLine(array);
    }

The resulting array contains the values you want.

---

You can create some extension methods to get the list of integers, or the list of bytes if you want.

    public static int[] GetIntegerValues(this BitArray bitArray)
    {
        var array = new int[bitArray.Length / (8 * sizeof(int))];
        bitArray.CopyTo(array, 0);
        return array;
    }
    public static byte[] GetByteValues(this BitArray bitArray)
    {
        var array = new byte[bitArray.Length / 8];
        bitArray.CopyTo(array, 0);
        return array;
    }

with some sample usage

    static void Main(string[] args)
    {
        var bits = new BitArray(new int[] { 15, int.MinValue, int.MaxValue });

        var int_array = bits.GetIntegerValues();
        var byte_array = bits.GetByteValues();

        Console.WriteLine(int_array);
        // {15, -2147483648, 2147483647}
        Console.WriteLine(byte_array);
        // {15,0,0,0, 0,0,0,128, 255,255,255,127}
    }