怎么只匹配4个数字

Question

using System;
using System.Text.RegularExpressions;class TestReg
{
  public static void Main()
  {
string str = "121231112and2323or22233434";
Regex re = new Regex(@"(?<!\d)\d{4}(?!\d)");
Match m = re.Match(str);
if (m.Success)
Console.WriteLine(m.Value); string[] slist = { "121231112and2323or22233434","1234","1234ab","ab1234","12345ad"};
re = new Regex(@"(?:^|\D+)(\d{4})(?:\D+|$)");
foreach (string s in slist)
{
Console.Write("{0}==>",s);
m = re.Match(s);
if (m.Success)
Console.Write("{0}",m.Groups[1].Value); Console.WriteLine();
}
  }
}

Answer 1

困扰我多时的问题解决了
谢谢思归兄！