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Groups > comp.lang.python > #18441

Re: .format vs. %

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On 2012-01-03, Stefan Krah <stefan-usenet@bytereef.org> wrote:
> Andrew Berg <bahamutzero8825@gmail.com> wrote:
>> To add my opinion on it, I find format() much more readable and easier
>> to understand (with the exception of the {} {} {} {} syntax), and would
>> love to see %-style formatting phased out.
>
> For me the %-style is much more readable. Also, it is significantly
> faster:
>
> $ ./python -m timeit -n 1000000 '"%s" % 7.928137192'
> 1000000 loops, best of 3: 0.0164 usec per loop

I have done a little more investigating, and the above is
arguably not fair. Python is interpolating that string at compile
time, as far as I can tell. Pretty cool, and not possible with
.format, but it's just regurgitating a string literal over and
over, which isn't of much interest.

% is faster, but not by an order of magnitude.

On my machine:

C:\WINDOWS>python -m timeit -n 1000000 -s "n=7.92" "'%s' % n"
1000000 loops, best of 3: 0.965 usec per loop

C:\WINDOWS>python -m timeit -n 1000000 -s "n=7.92" "'{}'.format(n)"
1000000 loops, best of 3: 1.17 usec per loop

-- 
Neil Cerutti

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.format vs. % davidfx <dgeorge29ca@gmail.com> - 2011-12-31 10:19 -0800
  Re: .format vs. % Andrew Berg <bahamutzero8825@gmail.com> - 2011-12-31 12:34 -0600
  Re: .format vs. % Yaşar Arabacı <yasar11732@gmail.com> - 2011-12-31 20:34 +0200
    Re: .format vs. % davidfx <dgeorge29ca@gmail.com> - 2011-12-31 10:44 -0800
    Re: .format vs. % davidfx <dgeorge29ca@gmail.com> - 2011-12-31 10:44 -0800
      Re: .format vs. % Yaşar Arabacı <yasar11732@gmail.com> - 2011-12-31 20:51 +0200
      Re: .format vs. % Evan Driscoll <edriscoll@wisc.edu> - 2011-12-31 13:47 -0500
        Re: .format vs. % Miki Tebeka <miki.tebeka@gmail.com> - 2012-01-01 13:11 -0800
          Re: .format vs. % Terry Reedy <tjreedy@udel.edu> - 2012-01-02 05:29 -0500
        Re: .format vs. % Miki Tebeka <miki.tebeka@gmail.com> - 2012-01-01 13:11 -0800
      Re: .format vs. % Alexander Kapps <alex.kapps@web.de> - 2011-12-31 19:59 +0100
      Re: .format vs. % Tim Chase <python.list@tim.thechases.com> - 2011-12-31 13:24 -0600
      Re: .format vs. % Lie Ryan <lie.1296@gmail.com> - 2012-01-01 06:34 +1100
      Re: .format vs. % Robert Kern <robert.kern@gmail.com> - 2011-12-31 19:43 +0000
      Re: .format vs. % Terry Reedy <tjreedy@udel.edu> - 2011-12-31 16:09 -0500
  Re: .format vs. % Ethan Furman <ethan@stoneleaf.us> - 2012-01-02 14:00 -0800
    Re: .format vs. % Rick Johnson <rantingrickjohnson@gmail.com> - 2012-01-02 17:59 -0800
      Re: .format vs. % Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-03 03:52 +0000
        Re: .format vs. % Ian Kelly <ian.g.kelly@gmail.com> - 2012-01-02 22:58 -0700
          Re: .format vs. % Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-03 06:15 +0000
            Re: .format vs. % Ian Kelly <ian.g.kelly@gmail.com> - 2012-01-03 01:16 -0700
            Re: .format vs. % Ethan Furman <ethan@stoneleaf.us> - 2012-01-03 05:26 -0800
            Re: .format vs. % Ethan Furman <ethan@stoneleaf.us> - 2012-01-03 11:38 -0800
            Re: .format vs. % Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-03 15:02 -0500
            Re: .format vs. % Ethan Furman <ethan@stoneleaf.us> - 2012-01-03 12:16 -0800
        Re: .format vs. % Andrew Berg <bahamutzero8825@gmail.com> - 2012-01-03 04:55 -0600
        Re: .format vs. % Stefan Krah <stefan-usenet@bytereef.org> - 2012-01-03 12:47 +0100
          Re: .format vs. % Neil Cerutti <neilc@norwich.edu> - 2012-01-03 13:58 +0000
            Re: .format vs. % Stefan Krah <stefan-usenet@bytereef.org> - 2012-01-03 15:17 +0100
              Re: .format vs. % Neil Cerutti <neilc@norwich.edu> - 2012-01-03 15:15 +0000
                Re: .format vs. % Neil Cerutti <neilc@norwich.edu> - 2012-01-03 15:24 +0000
          Re: .format vs. % Neil Cerutti <neilc@norwich.edu> - 2012-01-03 19:46 +0000
            Re: .format vs. % Ethan Furman <ethan@stoneleaf.us> - 2012-01-03 12:00 -0800
            Re: .format vs. % Stefan Krah <stefan-usenet@bytereef.org> - 2012-01-03 21:53 +0100
        Re: .format vs. % Chris Angelico <rosuav@gmail.com> - 2012-01-04 00:04 +1100
  Re: .format vs. % Rick Johnson <rantingrickjohnson@gmail.com> - 2012-01-02 17:51 -0800
    Re: .format vs. % Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-03 03:47 +0000
  Re: .format vs. % 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-03 07:47 -0800
    Re: .format vs. % alex23 <wuwei23@gmail.com> - 2012-01-03 18:26 -0800
      Re: .format vs. % 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-04 00:25 -0800
        Re: .format vs. % alex23 <wuwei23@gmail.com> - 2012-01-04 16:23 -0800
          Re: .format vs. % 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-04 17:41 -0800

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