How to regex with negative search?

Question

I want to search a document for the following string

<whoName>[substring]</whoName>

where substring != "self"

so

<whoName>other</whoName>

would pass.

but

<whoName>self</whoName>

would fail

anubhava · Accepted Answer · 2015-09-05T14:08:46.583

4

You can use this negative lookahead based regex:

<(whoName)>(?!self\s*<).*?<\/\1>

RegEx Demo

Regex breakup:

<(whoName)>  # Match <whoName> and capture it ($1)
(?!self\s*<) # Negative lookahead that means current position is not followed by literal 
             # self followed by 0 or more spaces and <
.*?          # Match 0 or more characters (non-greedy)
<\/\1>       # Match closing tag using back-reference to captured group #1

edited Sep 05 '15 at 14:08

answered Sep 05 '15 at 14:03

anubhava

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This regex not match selfie or any substring that starts with self – Santiago Sep 05 '15 at 14:05
Yes, I was updating and writing more details. Please check updated answer now. – anubhava Sep 05 '15 at 14:09

score 1 · Answer 2 · answered Sep 05 '15 at 14:04

1

Use this regex:

^<whoName>((?!self<).)*</whoName>

Tested in notepad++ and regex101

answered Sep 05 '15 at 14:04

Santiago

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score 1 · Answer 3 · edited May 23 '17 at 11:58

1

You can find the solution here.

You could use something like

<whoName>(?!self)[a-z0-9]*<\/whoName>

(try this out here: https://regex101.com/r/vW8sP3/1).

As you can imagine the relevant part is (?!self).

edited May 23 '17 at 11:58

Community

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answered Sep 05 '15 at 14:07

michele

169
4

How to regex with negative search?

3 Answers3