CODEWITHSUNDEEP
regex
Hermie
Hermie

Reputation: 53

Regex to match string if NOT only string on line

I want to match nvalue if it's NOT the only string on a line.

nvalue : should not match
This nvalue : should match
Nvalue example : should match

I know the regex to match nvalue if it's the only string:

^\bnvalue\b$

but I don't know how to turn it around.

Upvotes: 1

Views: 88

Answers (2)

Shakiba Moshiri
Shakiba Moshiri

Reputation: 23914

You can use match-group and operator | as alternation to match both possibilities:

((\w+ nvalue)|(nvalue \w+))

and it works on all regex-search-engine

with flags g : global
............... i : case-sensitive
................m : multi-line

or:

((\w+ [Na]value)|([Na]value \w+))

Upvotes: 1

Dmitry Egorov
Dmitry Egorov

Reputation: 9650

Use negative lookbehind:

 ^(?!nvalue$).*nvalue

Here ^(?!nvalue$) means match beginning of a string only is it is not followed by nvalue and end of string $ immediately after that.

Demo: https://regex101.com/r/1vOhQt/1

Update

If you need to extract the nvalue only, wrap it into a capture group using parenthesis:

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

The result will be stored in the first match group. Demo: https://regex101.com/r/1vOhQt/3.

If you're using PCRE flavour, use \K to reset any previously matched subpattern:

^(?!nvalue$).*\Knvalue

Demo: https://regex101.com/r/1vOhQt/2

In Python the \K is supported in regex module.

Upvotes: 2

Related Questions