C# 从字符串中获取最后一组数字的正则表达式

这就是我目前所做的，但我没有得到正确的结果

"abc_d1.txt" should get 0
"abc_d1_2.txt" should get 2
"abc_d1_14.txt" should get 14
"abc_d12_x2_156.txt" should get 156

---

您可以使用此正则表达式：

  string y = "tester_yg1.txt";
  string pattern = @"(\d+)(?!.*\d)";
  Regex rg = new Regex(pattern);
  var z = rg.Match(fullFileName).Value;
  Console.WriteLine($"z is {z}");

---

现在z1应该包含删除了编号和扩展名的文件名。当没有数字时，它将返回不带扩展名的文件名。

另一个选项是使用一组正向查找

string pattern1 =  @"_\d+(?=\.\w+)|(?<!_\d+)(?=\.\w+)";
Regex rg1 = new Regex(pattern1);
var z = rg1.Replace(y, "");
string z1  = Path.GetFilename(z);

（？使用

（？
看

解释

(?<=_[^\W\d_]\d+_?)\d*(?=\.\w+$)

--------------------------------------------------------------------------------
（？“abc_d1.txt”应该得到0-正则表达式无法匹配字符串中未找到的字符！您必须将空匹配项转换为0。@PoulBak是的，我也这么认为。谢谢。如果您不介意，我可以添加一个附加问题吗？例如：“abc_d1_14.txt”如何得到相反的结果？结果应该是“abc_d1”和“abc_d12_x2_156.txt”结果应为“abc\U d12\U x2”
(?<=_[^\W\d_]\d+_?)\d*(?=\.\w+$)

--------------------------------------------------------------------------------
  (?<!                     look behind to see if there is not:
--------------------------------------------------------------------------------
    [^\W_]                   any character except: non-word
                             characters (all but a-z, A-Z, 0-9, _),
                             '_'
--------------------------------------------------------------------------------
  )                        end of look-behind
--------------------------------------------------------------------------------
  \d+                      digits (0-9) (1 or more times (matching
                           the most amount possible))
--------------------------------------------------------------------------------
  (?=                      look ahead to see if there is:
--------------------------------------------------------------------------------
    \.                       '.'
--------------------------------------------------------------------------------
    \w+                      word characters (a-z, A-Z, 0-9, _) (1 or
                             more times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    $                        before an optional \n, and the end of
                             the string
--------------------------------------------------------------------------------
  )                        end of look-ahead