C#Regex - 如何从字符串中删除多个配对的括号

Question

我试图弄清楚如何使用C#正则表达式从字符串中删除所有实例配对括号.应删除括号和它们之间的所有文本.括号并不总是在同一条线上.此外,它们可能是嵌套的括号.字符串的一个例子是

This is a (string). I would like all of the (parentheses
to be removed). This (is) a string. Nested ((parentheses) should) also
be removed. (Thanks) for your help.

所需的输出应如下:

This is a . I would like all of the . This  a string. Nested  also
be removed.  for your help.

Answer 1

幸运的是,.NET允许在正则表达式中递归(请参阅平衡组定义):

Regex regexObj = new Regex(
    @"\(              # Match an opening parenthesis.
      (?>             # Then either match (possessively):
       [^()]+         #  any characters except parentheses
      |               # or
       \( (?<Depth>)  #  an opening paren (and increase the parens counter)
      |               # or
       \) (?<-Depth>) #  a closing paren (and decrease the parens counter).
      )*              # Repeat as needed.
     (?(Depth)(?!))   # Assert that the parens counter is at zero.
     \)               # Then match a closing parenthesis.",
    RegexOptions.IgnorePatternWhitespace);

如果有人想知道:"parens计数器"可能永远不会低于零(<?-Depth>否则会失败),所以即使括号是"平衡的"但没有正确匹配(如()))((()),这个正则表达式也不会被愚弄.

欲了解更多信息,请阅读Jeffrey Friedl的优秀着作"掌握正则表达式"(第436页)