From: luke <l.d.u.n.c.a.l.f.e@...> (dot)
Date: 2005-09-05T13:11:28+09:00
Subject: Re: Making my Regex less greedy?


Thanks very much, that works a treat. Always nice to have something
demonstrated in Lewis Carroll.

So, {100,#{m.length}}? effectively is now finding the first match, if any
.... Out of curiosity, is it easy to express "find the 3rd match"?. (Rather
than saying "find 3 matches").

Luke


"Gavin Kistner" <gavin@refinery.com> wrote in message
news:3844E43F-DA57-489D-9DA1-4E5FF239A296@refinery.com...
> On Sep 4, 2005, at 5:51 PM, luke wrote:
> > The logic I'd like the above regex to operate with is: "Starting 100
> > characters into the message, chop the message at the next paragraph
> > break".
>
> The question mark makes quantifiers non-greedy.
> + versus .+?
> * versus .*?
> {a,b} versus .{a,b}?
>
> For example:
> txt = <<END
> Twas brillig
> and the slithy toves
> did gyre and gimble
> in the wabe
> END
>
> def truncate_after( str, length )
>      str =~ /\A(.{#{length},}?)\n(.+)/m
>      return [ $1, $2 ]
> end
>
> p truncate_after( txt, 0 )
> #=>["Twas brillig", "and the slithy toves\ndid gyre and gimble\nin
> the wabe\n"]
>
> p truncate_after( txt, 20 )
> #=>["Twas brillig\nand the slithy toves", "did gyre and gimble\nin
> the wabe\n"]
>
> p truncate_after( txt, 40 )
> #=>["Twas brillig\nand the slithy toves\ndid gyre and gimble", "in
> the wabe\n"]
>
>
>