C#正则函数用法实例【匹配、替换、提取】

/// 

/// 邮箱格式验证
/// 
/// 
public static string CheckMail(string strEmail)
{
  string result = "";
  Regex regex = new Regex(@"[a-zA-Z0-9._%-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}");
  Match match = regex.Match(strEmail);
  if(match.Success)
  {
    result = strEmail;
  }
  else
  {
    result = "无效邮箱";
  }
  return result;
}

/// 

/// 转换日期格式（yyyy-MM-dd 转 yyyy年MM月dd日）
/// 
/// 
/// 
public static string TransDate(string strDate)
{
  string result = "";
  Regex regex = new Regex(@"(\d+)-(\d+)-(\d+)");
  if(regex.IsMatch(strDate))
  {
    result = regex.Replace(strDate,"$1年$2月$3日");
  }
  return result;
}

/// 

/// 正则表达式提取和替换内容
/// 
public static string Contentextract()
{
  string result = "";
  string str = "大家好! 张三 自我介绍。";
  Regex regex = new Regex(@"[\s\S]*&＃63;)'\s+Email='(&＃63;[\s\S]*&＃63;)'>(&＃63;[\s\S]*&＃63;)", RegexOptions.IgnoreCase);
  Match match = regex.Match(str);
  if(match.Success)
  {
    string userName = match.Groups["userName"].Value; //获取用户名
    string time = match.Groups["time"].Value; //获取入职时间
    string email = match.Groups["email"].Value; //获取邮箱地址
    string strFormat = String.Format("我是：{0}，入职时间：{1}，邮箱：{2}", userName, time, email);
    result = regex.Replace(str, strFormat); //替换内容
    Console.WriteLine(result);
  }
  return result;  //结果：大家好！我是张三，入职时间：2010-10-7，邮箱：zhangsan@163.com 自我介绍。
}

/// 

/// 从XML中提取匹配的字段
/// 
/// 
static void Main(string[] args)
{
  string strXml = GetStrXml(); //创建用户信息XML
  Regex userRegex = new Regex(@"[\s\S]*&＃63;)'\s+Email='(&＃63;[\s\S]*&＃63;)'>(&＃63;[\s\S]*&＃63;)", RegexOptions.IgnoreCase);
  MatchCollection userMatchColl = userRegex.Matches(strXml);
  if (userMatchColl.Count > 0)
  {
    foreach (Match matchItem in userMatchColl)
    {
      string userName = matchItem.Groups["userName"].Value; //获取用户名
      string time = TransDate(matchItem.Groups["time"].Value); //获取入职时间，并转换日期格式
      string email = CheckMail(matchItem.Groups["email"].Value); //获取邮箱地址，并检测邮箱格式
      string strFormat = String.Format("姓名：{0}，入职时间：{1}，邮箱：{2}", userName, time, email);
      Console.WriteLine(strFormat);
    }
  }
  Console.ReadLine();
}
/// 

/// 创建用户信息XML
/// 
/// 
public static string GetStrXml()
{
  StringBuilder strXml = new StringBuilder();
  strXml.Append("");
  strXml.Append("张三");
  strXml.Append("李四");
  strXml.Append("王五");
  strXml.Append("");
  return strXml.ToString();
}