Get words in parenthesis as a group regex-CodePudding

String1: {{word1|word2|word3 (word4 word5)|word6}}

String2: {{word1|word2|word3|word6}}

With this regex sentence:

(?<=\{\{)(\w (?:\s \w )*)\|(\w (?:\s \w )*)\|(\w (?:\s \w )*)\|(\w (?:\s \w )*)(?=\}\})

I capture String2 as groups. How can I change the regex sentence to capture (word4 word5) also as a group?

CodePudding user response：

You can add a (?:\s*(\([^()]*\)))? subpattern:

(?<=\{\{)(\w (?:\s \w )*)\|(\w (?:\s \w )*)\|(\w (?:\s \w )*)(?:\s*(\([^()]*\)))?\|(\w (?:\s \w )*)(?=\}\})

See the regex demo.

The (?:\s*(\([^()]*\)))? part is an optional non-capturing group that matches one or zero occurrences of

\s* - zero or more whitespaces
( - start of a capturing group:
- \( - a ( char
- [^()]* - zero or more chars other than ( and )
- \) - a ) char
) - end of the group.

If you need to make sure only whitespace separated words are allowed inside parentheses, replace [^()]* with \w (?:\s \w )* and insert (?:\s*(\(\w (?:\s \w )*\)))?:

(?<=\{\{)(\w (?:\s \w )*)\|(\w (?:\s \w )*)\|(\w (?:\s \w )*)(?:\s*(\(\w (?:\s \w )*\)))?\|(\w (?:\s \w )*)(?=\}\})

See this regex demo.

CodePudding user response：

You could simplify the expression by matching the desired substrings rather than capturing them. For that you could use the following regular expression.

(?<=[{| ])\w (?=[}| ])|\([\w ] \)

Regex demo _{^<¯\(ツ)/¯^>} Python demo

The elements of the expression are as follows.

(?<=     # begin a positive lookbehind
  [{| ]  # match one of the indicated characters
)        # end the positive lookbehind
\w       # match one or more word characters
(?=      # begin a positive lookahead
  [}| ]  # match one of the indicated characters
)        # end positive lookahead
|        # or
\(       # match character
[\w ]    # match one or more of the indicated characters 
\)       # match character

Note that this does not validate the format of the string.