正则表达式平衡组

时间:2012-02-06 04:09:50

标签: c# regex balancing-groups

我正在尝试在字符串中匹配平衡大括号({})。例如,我想平衡以下内容:

if (a == 2)
{
  doSomething();
  { 
     int x = 10;
  }
}

// this is a comment

while (a <= b){
  print(a++);
} 

我从MSDN中得到了这个正则表达式,但是效果不好。我想提取多个{}的嵌套匹配集。我只对父母比赛感兴趣

   "[^{}]*" +
   "(" + 
   "((?'Open'{)[^{}]*)+" +
   "((?'Close-Open'})[^{}]*)+" +
   ")*" +
   "(?(Open)(?!))";

1 个答案:

答案 0 :(得分:5)

你非常接近。

改编自this question的第二个答案(我使用它作为我的规范“在C#/ .NET正则表达式引擎中平衡xxx”的答案,如果它对你有所帮助就提升它!它在过去帮助了我):

var r = new Regex(@"
[^{}]*                  # any non brace stuff.
\{(                     # First '{' + capturing bracket
    (?:                 
    [^{}]               # Match all non-braces
    |
    (?<open> \{ )       # Match '{', and capture into 'open'
    |
    (?<-open> \} )      # Match '}', and delete the 'open' capture
    )+                  # Change to * if you want to allow {}
    (?(open)(?!))       # Fails if 'open' stack isn't empty!
)\}                     # Last '}' + close capturing bracket
"; RegexOptions.IgnoreWhitespace);