For Abba... Why doesn't (.)(.)\2[^\1] work? I thought backreferences matched the... | Hacker News

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scott_karana on Dec 20, 2013 | parent | context | favorite | on: Regex Golf

For Abba...

Why doesn't (.)(.)\2[^\1] work?

I thought backreferences matched the captured literal, so negating it would match? But this looks the same as (.)(.)\2\1...

goldenkey on Dec 20, 2013 | [–]

You cannot negate a capture, only a character literal. A capture might only be a character but it is NOT a literal,

scott_karana on Dec 20, 2013 | | [–]

Gotcha. That makes perfect sense. Thank you! :)

goldenkey on Dec 21, 2013 | | | [–]

You got it :-)

annasaru on Dec 20, 2013 | [–]

(.)(.)\2\1 ?

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