using System;

using System.Linq;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

            const string frequencies = "a2#b2#c2#d2#e2#\r1#\n1#\0";

            var dictionary = Regex.Matches(frequencies, @".\d+.", RegexOptions.Singleline).Cast<Match>().ToDictionary(x => Convert.ToByte(x.Value[0]), x => int.Parse(x.Value.Substring(1, x.Value.Length - 2)));

            foreach (var item in dictionary)

            {

                Console.WriteLine("{0} : {1}", item.Key, item.Value);

            }

    }

}