Negative Regex pattern matching in python

Question

I have the two below lines as output

   1   ID_1    INSV  enabled   Activated   12.345.67.89
   2   ID_2    SYSB  Disabled  Activated    12.345.67.89

I want to match the lines that should NOT have SYSB but it should have Activated. I am writing the below regex

ID_\d+\s+(?!SYSB)\s+\w+\s+Activated

It ignores the SYSB line, but its not capturing INSV line too. How to solve this regex?

Wouldn't it be easier to just check each line and use the `in`, `and`, `not` operators instead? — Sweeper, Sep 06 '19 at 07:21
A compiled regex should perform better depending on the number of rows. — Adirio, Sep 06 '19 at 07:22
While @anubhava answer works, I wanted to answer your question directly. Your regex is not matching cos it doesn't have anything that matches the word in place of SYSB. The corrected version could be: `ID_\d+\s+(?!SYSB)\w*\s+\w+\s+Activated` adding that \w* to match `INSV` in your example case. — Adirio, Sep 06 '19 at 07:28

score 1 · Accepted Answer · answered Sep 06 '19 at 07:21

You may use negative lookahead like this:

^(?!.* SYSB ).* Activated\b

RegEx Details:

^: Start
(?!.* SYSB ): Negative lookahead to fail the match if " SYSB " is present anywhere in the line
.* Activated\b: Match word Activated anywhere in the line after a space. \b is for word boundary.

1 Answers1