regex to match comma delimited

            string pattern = @"^(\w)(?:(?:,(\w))*)$";
            List<char> list = new List<char>();
            foreach(Match m in Regex.Matches(s, pattern))
            {
                string msg = "";
                for(int i = 1; i < m.Groups.Count; i++)
                {
                    Group g = m.Groups[i];
                    if(g.Value != "")
                    {
                        Debug.Log(g.Value[0]);
                        list.Add(g.Value[0]);
                    }
                }
            }