CODEWITHSUNDEEP
regex
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Reputation: 333

Regex: Combine negative lookahead and regular search

I would like to combine two regular expressions. The first one is a negative lookahead:

^(.(?!(test)))*$

It matches my data that does not contain "test".

Now I would like to combine it with a basic search: I would like to find data that does not contain "test" (string 1) but does contain "fix" (string 2). How can I combine these two into a single regular expression?

For my purpose it doesn't matter where these strings appear, as long as "test" does not appear and "fix" does appear.

Upvotes: 2

Views: 2749

Answers (2)

user557597
user557597

Reputation:

Either of these ways will work:

Type 1 

 # ^(?!.*test)(?=.*fix).*$

 ^ 
 (?! .* test )
 (?= .* fix )
 .* 
 $

Type 2 

 # ^(?:(?!test).)*fix(?:(?!test).)*$

 ^ 
 (?:
      (?! test )
      . 
 )*
 fix
 (?:
      (?! test )
      . 
 )*
 $

Upvotes: 1

R Nar
R Nar

Reputation: 5515

^(?!.*test)(?=.*fix)(.*)$

Regular expression visualization

Debuggex Demo

is a general solution for this. it doesn't really matter what order the lookarounds are in since the regex cursor will not move until the lookarounds have been parsed.

the only thing I want to say about this, and I made it this way because thats what your regex is like, is that if there are words like fixed or tested, those will be caught by the look aheads. you can change this by adding word boundaries

^(?!.*\btest\b)(?=.*\bfix\b)(.*)$

EDIT: if you want to match across multiple lines, take out /m and replace with /s or change . token

^(?![\s\S]*test)(?=[\s\S]*fix)([\s\S]*)$

Upvotes: 5

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