Regex Match All Unless?

Question

Assuming I want:

TESTGRID - NOT MATCH
testgrid - NOT MATCH
ACTIVEID - MATCH
activeID - MATCH
testRID - MATCH

I've tried:

(?!([^GR]))ID*?\b (I really thought I had it with this one - Don't match ID if it is preceeded with GR, right?
(?!([^GRID]))ID*?\b
(?!([GRID]))ID*?\b

None of which is working.

I swear I'm getting better with regex, though :) I've managed to knock out the last 6 attempts without seeking help from SO, but I'm once again stuck :(

Answer 1

Don't match ID if it is preceeded with GR

If you mean to match ID that is at the end of the word, and is not preceded with GR , use

(?<!GR)ID\b

See this regex demo

Note that (?<!GR) is a negative lookbehind that fails the match if the lookbehind pattern finds a match to the left of the current position in the string. If you use [^GR] , a negated character class, then only one single symbol/character is checked for (a character other than G and R ), not a character sequence .