使用正则找重复单词

 private void button1_Click(object sender, EventArgs e)

        {

            System.Text.RegularExpressions.MatchCollection matches =//使用正则表达式查找重复出现单词的集合

                System.Text.RegularExpressions.Regex.Matches(label1.Text,

                @"\b(?<word>\w+)\s+(\k<word>)\b", System.Text.

                RegularExpressions.RegexOptions.Compiled | System.Text.

                RegularExpressions.RegexOptions.IgnoreCase);

            if (matches.Count != 0)//如果集合中有内容

            {

                foreach (System.Text.RegularExpressions.Match//遍历集合

                    match in matches)

                {

                    string word = match.Groups["word"].Value;//获取重复出现的单词

                    MessageBox.Show(word.ToString(), "英文单词");//弹出消息对话框

                }

            }

            else { MessageBox.Show("没有重复的单词"); }//弹出消息对话框

        }



        private void Form1_Load(object sender, EventArgs e)

        {

            label1.Text =//创建字符串对象

                "The the quick brown fox  fox jumped over the lazy dog dog.";

        }