用正则表达式替换C#美元问题

Question

我想在两个命名的捕获组之间的特定位置插入一个美元符号.问题是这意味着两个紧跟在替换字符串中的美元符号之后会导致问题.

我如何使用Replace-method直接执行此操作？我只是通过添加一些临时垃圾找到了解决方法,我立即再次删除.

请参阅问题的代码:

      // We want to add a dollar sign before a number and use named groups for capturing;
      // varying parts of the strings are in brackets []
      // [somebody] has [some-dollar-amount] in his [something]

      string joeHas = "Joe has 500 in his wallet.";
      string jackHas = "Jack has 500 in his pocket.";
      string jimHas = "Jim has 740 in his bag.";
      string jasonHas = "Jason has 900 in his car.";

      Regex dollarInsertion = new Regex(@"(?<start>^.*? has )(?<end>\d+ in his .*?$)", RegexOptions.Multiline);

      Console.WriteLine(joeHas);
      Console.WriteLine(jackHas);
      Console.WriteLine(jimHas); 
      Console.WriteLine(jasonHas);
      Console.WriteLine("--------------------------");

      joeHas = dollarInsertion.Replace(joeHas, @"${start}$${end}");
      jackHas = dollarInsertion.Replace(jackHas, @"${start}$-${end}");          
      jimHas = dollarInsertion.Replace(jimHas, @"${start}\$${end}");
      jasonHas = dollarInsertion.Replace(jasonHas, @"${start}$kkkkkk----kkkk${end}").Replace("kkkkkk----kkkk", "");

      Console.WriteLine(joeHas);
      Console.WriteLine(jackHas);
      Console.WriteLine(jimHas);
      Console.WriteLine(jasonHas);




Output:
Joe has 500 in his wallet.
Jack has 500 in his pocket.
Jim has 740 in his bag.
Jason has 900 in his car.
--------------------------
Joe has ${end}
Jack has $-500 in his pocket.
Jim has \${end}
Jason has $900 in his car.

Answer 1

使用此替换模式: "${start}$$${end}"

双重$$逃脱,$以便将其视为文字字符.第三个$实际上是命名组的一部分${end}.您可以在MSDN Substitutions页面上阅读相关内容.

我会坚持上述方法.或者,您可以使用Replace接受MatchEvaluator并连接所需内容的重载,类似于以下内容:

jackHas = dollarInsertion.Replace(jackHas,
              m => m.Groups["start"].Value + "$" + m.Groups["end"].Value);