HexToByteArray

Converts a hexadecimal string to a byte array.

• Use Enumerable.Range() in combination with string.Length to get the indices of the given string in an array.
• Use Enumerable.Where() to get only the even indices in the previous range.
• Use Enumerable.Select() in combination with Convert.ToByte() and string.Substring() to convert each byte's hex code to a byte.
• Finally, use Enumerable.ToArray() to return a byte[].

using System.Linq;

public static partial class _30s 
{
  public static byte[] HexToByteArray(string hex)
  {
    return Enumerable.Range(0, hex.Length)
      .Where(x => x % 2 == 0)
      .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
      .ToArray();
  }
}

_30s.HexToByteArray("F15936"); // { 241, 89, 54 }