What is built-in method sub

Jeremy jlconlin at gmail.com
Mon Jan 11 21:30:07 CET 2010


On Jan 11, 1:15 pm, "Diez B. Roggisch" <de... at nospam.web.de> wrote:
> Jeremy schrieb:
>
>
>
>
>
> > On Jan 11, 12:54 pm, Carl Banks <pavlovevide... at gmail.com> wrote:
> >> On Jan 11, 11:20 am, Jeremy <jlcon... at gmail.com> wrote:
>
> >>> I just profiled one of my Python scripts and discovered that >99% of
> >>> the time was spent in
> >>> {built-in method sub}
> >>> What is this function and is there a way to optimize it?
> >> I'm guessing this is re.sub (or, more likely, a method sub of an
> >> internal object that is called by re.sub).
>
> >> If all your script does is to make a bunch of regexp substitutions,
> >> then spending 99% of the time in this function might be reasonable.
> >> Optimize your regexps to improve performance.  (We can help you if you
> >> care to share any.)
>
> >> If my guess is wrong, you'll have to be more specific about what your
> >> sctipt does, and maybe share the profile printout or something.
>
> >> Carl Banks
>
> > Your guess is correct.  I had forgotten that I was using that
> > function.
>
> > I am using the re.sub command to remove trailing whitespace from lines
> > in a text file.  The commands I use are copied below.  If you have any
> > suggestions on how they could be improved, I would love to know.
>
> > Thanks,
> > Jeremy
>
> > lines = self._outfile.readlines()
> > self._outfile.close()
>
> > line = string.join(lines)
>
> > if self.removeWS:
> >     # Remove trailing white space on each line
> >     trailingPattern = '(\S*)\ +?\n'
> >     line = re.sub(trailingPattern, '\\1\n', line)
>
> line = line.rstrip()?
>
> Diez

Yep.  I was trying to reinvent the wheel.  I just remove the trailing
whitespace before joining the lines.

Thanks,
Jeremy



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