Regular expression to match a #

Devan L devlai at gmail.com
Fri Aug 12 00:58:21 CEST 2005


John Machin wrote:
> Devan L wrote:
> > John Machin wrote:
> >
> >>Aahz wrote:
> >>
> >>>In article <42fb45d7$1 at news.eftel.com>,
> >>>John Machin  <sjmachin at lexicon.net> wrote:
> >>>
> >>>
> >>>>Search for r'^something' can never be better/faster than match for
> >>>>r'something', and with a dopey implementation of search [which Python's
> >>>>re is NOT] it could be much worse. So please don't tell newbies to
> >>>>search for r'^something'.
> >>>
> >>>
> >>>You're somehow getting mixed up in thinking that "^" is some kind of
> >>>"not" operator -- it's the start of line anchor in this context.
> >>
> >>I can't imagine where you got that idea from.
> >>
> >>If I change "[which Python's re is NOT]" to "[Python's re's search() is
> >>not dopey]", does that help you?
> >>
> >>The point was made in a context where the OP appeared to be reading a
> >>line at a time and parsing it, and re.compile(r'something').match()
> >>would do the job; re.compile(r'^something').search() will do the job too
> >>-- BECAUSE ^ means start of line anchor -- but somewhat redundantly, and
> >>very inefficiently in the failing case with dopey implementations of
> >>search() (which apply match() at offsets 0, 1, 2, .....).
> >
> >
> > I don't see much difference.
>
> and I didn't expect that you would -- like I wrote above: "Python's re's
> search() is not dopey".

Your wording makes it hard to distinguish what exactly is "dopey".




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