正则表达式函数

1,

  #region 输入input匹配pattern的第index分组        
      
        /// <summary>
        /// 输入input匹配pattern的第index分组
        /// </summary>
        /// <param name="input">输入字符源</param>
        /// <param name="pattern">正则模式</param>
        /// <param name="index">第几个分组(分组用小括号)</param>
        /// <returns></returns>
        public static string MatchString(string input, string pattern, int index=0)
        {
            System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex(pattern);
            System.Text.RegularExpressions.Match match = regex.Match(input);
            if (match.Success)
            {
                return match.Groups[index].ToString();
            }
            else
            {
                return null;
            }
        }
        #endregion

2,

 #region 输入input匹配pattern的第index分组,输出所有匹配项
        /// <summary>
        /// 输入input匹配pattern的第index分组,输出所有匹配项   
        /// </summary>
        /// <param name="input">输入字符源</param>
        /// <param name="pattern">正则模式</param>
        /// <param name="index">第几个分组(分组用小括号)</param>
        /// <returns>所有匹配项</returns>
        public static List<string> MatchStrings(string input,string pattern,int index=0)
        {
            List<string> list = new List<string>();
            System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex(pattern);
            System.Text.RegularExpressions.Match match = regex.Match(input);
            //循环匹配
            while (match.Success)
            {
                list.Add(match.Groups[index].ToString());
                match = match.NextMatch();//匹配下一个
            }
            return list;
        }
        #endregion

总结：