CODEWITHSUNDEEP
regexexpressionnotepad++
KrzysztofJ
KrzysztofJ

Reputation: 23

Problem with regular expression using look behind feature

I try to build simple regular expression to remove some parts of bad (unwanted) code and needed use look behind feature.

It worked until i added \s+ to it to exclude spaces from mark.

Eliminating parts of expression i finally got to (?<=\s+)foo which is still warned as invalid expression.

It may looks a little weird or unclear so expanding it: (?<=foo\s+)bar is warned as invalid expression, where (?<=foo)\s+bar is working but it marks spaces before bar.

I am use it in notepad++.

Upvotes: 1

Views: 701

Answers (1)

The fourth bird
The fourth bird

Reputation: 163287

From the comment by @Toto Notepad++ does not support variable length lookbehind. It uses the boost regex.

Notepad++ does support \K to reset the starting point of the reported match. 

\bfoo\s+\Kbar\b

Regex demo

Another way is to capture bar in a capturing group.

\bfoo\s+(bar)\b

Regex demo

Note that \s also matches a newline, and perhaps you might also use \h+ to match 1+ horizontal whitespace characters.

Upvotes: 1

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