Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #38390

Re: Curious to see alternate approach on a search/replace via regex

Show all headers | View raw

On Thu, Feb 7, 2013 at 5:55 PM, Ian Kelly <ian.g.kelly@gmail.com> wrote:
> Whatever caching is being done by re.compile, that's still a 24%
> savings by moving the compile calls into the setup.

On the other hand, if you add an re.purge() call to the start of t1 to
clear the cache:

>>> t3 = Timer("""
... re.purge()
... nx = re.compile(r'https?://(.+)$')
... v = nx.search(u).group(1)
... ux = re.compile(r'([-:./?&=]+)')
... ux.sub('_', v)""", """
... import re
... u = 'http://alongnameofasite1234567.com/q?sports=run&a=1&b=1'""")
>>> min(t3.repeat(number=10000))
3.5532990924824617

Which is approximately 30 times slower, so clearly the regular
expression *is* being cached.  I think what we're seeing here is that
the time needed to look up the compiled regular expression in the
cache is a significant fraction of the time needed to actually execute
it.

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: Curious to see alternate approach on a search/replace via regex Demian Brecht <demianbrecht@gmail.com> - 2013-02-06 13:55 -0800
  Re: Curious to see alternate approach on a search/replace via regex Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-07 03:04 +0000
    Re: Curious to see alternate approach on a search/replace via regex rh <richard_hubbe11@lavabit.com> - 2013-02-06 19:31 -0800
      Re: Curious to see alternate approach on a search/replace via regex Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-08 09:45 +1100
        Re: Curious to see alternate approach on a search/replace via regex rh <richard_hubbe11@lavabit.com> - 2013-02-07 15:13 -0800
          Re: Curious to see alternate approach on a search/replace via regex Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-08 10:59 +1100
            Re: Curious to see alternate approach on a search/replace via regex Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-07 17:55 -0700
              Re: Curious to see alternate approach on a search/replace via regex Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-08 14:02 +1100
                Re: Curious to see alternate approach on a search/replace via regex rh <richard_hubbe11@lavabit.com> - 2013-02-07 21:35 -0800
            Re: Curious to see alternate approach on a search/replace via regex Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-07 18:08 -0700
            Re: Curious to see alternate approach on a search/replace via regex rh <richard_hubbe11@lavabit.com> - 2013-02-07 21:57 -0800
            Re: Curious to see alternate approach on a search/replace via regex Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-08 01:21 -0700
              Re: Curious to see alternate approach on a search/replace via regex Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-08 22:43 +1100
                Re: Curious to see alternate approach on a search/replace via regex Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-08 09:26 -0700
            Re: Curious to see alternate approach on a search/replace via regex Serhiy Storchaka <storchaka@gmail.com> - 2013-02-15 22:58 +0200
            Re: Curious to see alternate approach on a search/replace via regex rh <richard_hubbe11@lavabit.com> - 2013-02-26 11:20 -0800
        Re: Curious to see alternate approach on a search/replace via regex Dave Angel <davea@davea.name> - 2013-02-08 01:27 -0500
    Re: Curious to see alternate approach on a search/replace via regex jmfauth <wxjmfauth@gmail.com> - 2013-02-07 03:08 -0800
      Re: Curious to see alternate approach on a search/replace via regex Chris Angelico <rosuav@gmail.com> - 2013-02-07 23:44 +1100

csiph-web