From: Paul Battley <pbattley@...>
Date: 2006-07-07T19:55:04+09:00
Subject: Re: Regexp

On 07/07/06, Fred VD <outrelouxhe@yahoo.fr> wrote:
>  @a = "blabla1 blabla1 <math>test1<\math> blabla2 blabla2
> <math>test2<\math>"
>  @b = @a.gsub(/<math>.+<\math>/,'ok')
>
> I get "blabla1 blabla1 ok" instead of "blabla1 blabla1 ok blabla2
> blabla2 ok"

+ and * are greedy. Use +? and *? for non-greedy operation:

a = 'a b <x>c</x> d <x>e</x> f g'
a.gsub(%r!<x>.+?</x>!, 'ok')
=> "a b ok d ok f g"
a.gsub(%r!<x>.+</x>!, 'ok')
=> "a b ok f g"

A greedy expression will match up to the *last * occurrence of what
follows it in the expression, whereas a non-greedy expression will
match up to the *first* occurrence.

Paul.