//提取字符串中至少连续7位的数字            string txt = "www17736123780eeeee 7377091 ddddsssss7777777";            //找到的成功匹配的集合            MatchCollection mc = Regex.Matches(txt, @"\d{7,}");            foreach (Match m in mc)            {                Console.WriteLine(m.Value);                            }