Regex multiple exclusions

Question

I would like to make a regex that matches groups like abbc, where each letter is a different character.

it should contain three capture groups
all the capture groups should contain different characters
the second one should be matched exactly twice

Example:

bank (not matched, because the second and the third character is not the same)

rook (matched)

book (matched)

poop (not matched, because the first and the last character is the same)

So far I have been trying something like this:

(.)(.(?!\1))\2(.(?!\1)(?!\2))

This however matches poop too. How do I correct this?

Regex might not be the correct tool for this.

Anmol Singh Jaggi
– Anmol Singh Jaggi

2017-11-16 11:12:07 +00:00
Commented Nov 16, 2017 at 11:12 — Anmol Singh Jaggi
– Anmol Singh Jaggi, Commented Nov 16, 2017 at 11:12

Sebastian Proske · Accepted Answer · 2017-11-16 11:54:51Z

1

Your positioning of the lookaheads is a bit off, you can do it like

(.)(?!\1)(.)\2(?!\1|\2)(.)

See https://regex101.com/r/heBJar/1

You might need to apply anchors or word boundaries as needed. You should also consider using [a-z] or [[:alpha:]] or similar instead of the ..

answered Nov 16, 2017 at 11:54

Sebastian Proske

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