一段英文中出现的单词的次数

前一段时间面试的时候，遇到一道面试题：求一段英文中的每个字母出现的次数。

今天我不求每个字母出现的频率，我求一段英文中每个单词出现的频率。

class Program
    {
        static void Main(string[] args)
        {
            string text = @"He was one of the best string instrument players in our town. He could not read music, but if he heard a tune a few times, he could play it";
            Dictionary<string, int> wordfrequencies = CountWords(text);
            foreach (KeyValuePair<string,int> entry in wordfrequencies)
            {
                Console.WriteLine("{0}:{1}",entry.Key,entry.Value);
            }
            Console.ReadKey();
        }
        static Dictionary<string,int> CountWords(string text)
        {
            //创建单词到频率的新映射
            Dictionary<string, int> wordfrequencies = new Dictionary<string, int>();
            //将文本分解成单词
            string[] words = Regex.Split(text, @"\W+");
            //添加或更新映射
            foreach (string word in words)
            {
                if (wordfrequencies.ContainsKey(word))
                {
                    wordfrequencies[word]++;
                }
                else
                {
                    wordfrequencies[word] = 1;
                }
            }
            return wordfrequencies;
        }
    }