From: Robert Dober <robert.dober@...>
Date: 2007-06-04T20:28:56+09:00
Subject: Re: No way of looking for a regrexp match starting from a particular point in a string?

On 6/4/07, Trans <transfire@gmail.com> wrote:
>
>
> On Jun 4, 6:19 am, "Robert Dober" <robert.do...@gmail.com> wrote:
> > On 6/3/07, Kenneth McDonald <kenneth.m.mcdon...@sbcglobal.net> wrote:> I'm probably just missing something obvious, but I haven't found a way
> > > to match a regular expression against only part of a string, in
> > > particular only past a certain point of a string, as a way of finding
> > > successive matches. Of course, one could do a match against a string,
> > > take the substring past that match and do a match against the substring,
> > > and so on, to find all of the matches for the string, but that could be
> > > very expensive for very large strings.
> >
> > > I'm aware of the String.scan method, but that doesn't work for me
> > > because it doesn't return MatchData instances.
> >
> > > What I want is just something like regexp.match(string, n),
> >
> > Hmm apart of using #scan and #index with $~ as indicated, I do not
> > think that there is a performance penalty if you do
> >
> > rg.match(string[n..-1])
>
> How can that be? You have to create a whole new String.
Beating a dead man Tom? As mentioned I had a terrible slip to C in my
reasoning, no idea why :(
> If that can be avoided in the internal implementation then adding an optional offset
> index to #match is not an unreasonable idea.
>
> T.
>
>
>


-- 
You see things; and you say Why?
But I dream things that never were; and I say Why not?
-- George Bernard Shaw