Re: Another regex to solve ...

I've not done much testing but this seems to work by putting the capture in the look-behind.

knoppix@Microknoppix:~$ perl -E '
> for ( qw{ soap creep top groat loop } )
> {
>     say unless m{(?<=([aeiou]))\1p\z};
> }'
soap
top
groat
knoppix@Microknoppix:~$
[download]

I hope this is helpful.

Cheers,

JohnGG

Comment on Re: Another regex to solve ... Download Code

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Re^2: Another regex to solve ... by Not_a_Number (Prior) on Aug 18, 2011 at 23:34 UTC
`say unless m{(?<=([aeiou]))\1p\z};` That allows eg 'help' or slurp'. Update: I've no idea why though, or why it also allows 'hops' and 'hoops'... Update 2: Got it! It also of course allows 'rabbit', or any other string that doesn't end in 'p' preceded by whatever. It was the `unless` that momentarily confused me. :)	[reply] [d/l] [select]
Re^3: Another regex to solve ... by johngg (Canon) on Aug 19, 2011 at 17:38 UTC
Yes, that was a pretty woeful attempt on my part. I must have been thinking about a sub-set of words all ending with 'p' rather than the general case :-( Cheers, JohnGG	[reply]
Re^2: Another regex to solve ... by pat_mc (Pilgrim) on Aug 19, 2011 at 19:35 UTC
Hi, johngg - I like the approach of back-referencing the match from the look-behing ... the only issue I have with the code you propose is that it over-generates in the sense that it will also pass strings all other strings that do not match the regex like 'stp' ... and that, of course, it shouldn't since we only want words to pass that have a non-double vowels in front of the word-terminal 'p'.	[reply]