统计单词数量并按个数多少降序排列

  //存储单词的数量 和 单词的内容
        struct myword
        {
            public string word { get; set; }
            public int count { get; set; }

            public override string ToString()
            {
                return string.Format("{0}:{1}", word, count);
            }
        }

        //计算单词个数
        protected void countWords(string content)
        {
            List<myword> wordlist = new List<myword>();
            MatchCollection mc = Regex.Matches(content, @"[a-zA-Z]+\b");
            foreach (Match m in mc)
            {
                myword word = wordlist.Find((w) =>
                {
                    return w.word.ToLower() == m.Value.ToLower();
                });
                if (word.count == 0)//如果是初次添加
                {
                    wordlist.Add(new myword { word = m.Value, count = 1 });
                }
                else
                {
                    wordlist.Remove(word);
                    wordlist.Add(new myword { word = m.Value, count = word.count + 1 });
                }
            }
            //按count由高到低排序
            wordlist.Sort(
               (x, y) =>
               {
                   return y.count.CompareTo(x.count);
               }
                );
            wordlist.ForEach( w => Console.WriteLine(w) );   
        }