正则表达式中的组集合的使用_.net资料_编程技术-你的首页-uuhomepage.com                
简单实例:
    string s = "2005-2-21"; 
    Regex reg = new Regex(@"(?\d{4})-(?\d{1,2})-(?\d{1,2})",RegexOptions.Compiled); 
          
    Match match = reg.Match(s); 
    int year =  int.Parse(match.Groups["y"].Value); 
    int month = int.Parse(match.Groups["m"].Value);
    int day = int .Parse(match.Groups["d"].Value); 
    DateTime time = new DateTime(year,month,day);