1 string str = "sztq数字提取123sztq数字提取";

2 string result = System.Text.RegularExpressions.Regex.Replace(str, @"[^0-9]+", "");

3 Console.WriteLine("使用正则表达式提取");

4 Console.WriteLine(result);

 1  string str = "sztq数字提取123sztq数字提取";

 2  foreach (char c in str)

 3          {

 4              if (Convert.ToInt32(c) >= 48 && Convert.ToInt32(c) <= 57)

 5               {

 6                   sb.Append(c);

 7               }

 8          }

 9  Console.WriteLine("使用ASCII码提取");

10  Console.WriteLine(sb.ToString());