正则表达式获取大括号之间的文本，包括其他大括号

Question

I have a "main"-string like:

((Gripper|Open==true OR RIT|Turning==false) AND Robot|PosX >=3 OR (Test|Close==false OR (Gripper|Open==false AND RIT|Turning==false)))

I want to get three sub strings in the best case:

1: (Gripper|Open==true OR RIT|Turning==false)
2: Robot|PosX >=3
3: (Test|Close==false OR (Gripper|Open==false AND RIT|Turning==false))

But only two (the one in braces [1,3]) would be fine too, since they can be replaced in the main-string, getting the 3rd[2] as a result. Ideally with the help of regex.

All the sub strings go into a class as children so I can apply the regex for each child and get their sub strings as well.

1: Test|Close==false
2: (Gripper|Open==false AND RIT|Turning==false)

For child number three (where the first result without the braces would be optional again.

I tried something similar to Regular expression to extract text between braces and putting positions of the matches onto a stack, but not with the expected results.

The best regex I found so far is

([^()]+(?:[^()]+)+) or
([^()]+(?:)+)

(seriously, regex is powerful, but I have no idea what the above statements really do) which gives me

 1. Gripper|Open == true OR RIT|Turning==false
 2. AND Robot|PosX >=3 OR
 3. Test|Close==false OR
 4. Gripper|Open==false AND RIT|Turning==false

But still, 3+4 should be in only one group as

 Test|Close==false OR (Gripper|Open==false AND RIT|Turning==false)

Does anyone know how to achieve this?

Answer 1

You may try with that:

(?<=\))(?!\()[^()]+|\((?!\()[^)]+\)

Regex101

Explanation:

(?<=\))(?!\()[^()]+ OR \((?!\()[^)]+\)

The first part before 'OR' basically matches AND Robot|PosX >=3 OR

1. (?<=\\)) negative lookbehind: match current character if the previous character is not )
2. (?!\\() negative lookahead : match current character if the next charcter is not ( or )
3. [^()]+ matches anything that is Neither ( nor ).

The last part after OR matches anything that starts with ( and ends with ) while ignoring any opening braces inside it.

Answer 2

It seems like you are looking for balanced parenthesis where the matches start with 2 words divided by a pipe and then an operator followed by an equals sign

In C# you might match either the balanced parenthesis or match a pattern that does not contain them using an alternation.

(?:\(\w+\|\w+\s*[<>!=]{1,2}[^()]*(?>[^()]+|(?<o>)\(|(?<-o>)\))*(?(o)(?!)|)\)|\w+\|\w+\s*[<>!=]{1,2}\S+)

• (?: Non capture group
  • \\(\\w+\\|\\w+\\s* Match ( then 2 words divided by a pipe and 0+ whitespace chars
  • [<>!=]{1,2}[^()]* Match any of the operators and match any char except ()
  • (?> Atomic group
    • [^()]+ Match 1+ times any char except ()
    • | Or
    • (?<o>)\\( Add to stack
    • | Or
    • (?<-o>)\\) Remove from stack
  • )* Close atomic group and repeat 0+ times
  • (?(o)(?!)|)\\) Conditional with capturing group, evaluate the final subpattern
  • | Or
  • \\w+\\|\\w+\\s*[<>!=]{1,2}\\S+ Match 2 words divided by a pipe and match operators
• ) Close non capture group

Regex demo