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Re: performance of script to write very long lines of random chars

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On Thu, Apr 11, 2013 at 12:40 PM, gry <georgeryoung@gmail.com> wrote:
> Appealing idea, but it's slower than the array solution: 5min 13
> secs.  vs 4min 30sec for the array:
>
> for l in range(rows):
>     for i in xrange(nchars):
>         stdout.write(random.choice(avail_chrs))
>     stdout.write('\n')
>
>
> os.urandom does look promising -- I have to have full control over the
> charset, but urandom is very fast at generating big random strings...
> stay tuned...

Without actually profiling it, my first guess would be that calling
random.choice() for every character is an optimization target. (NOTE:
Do profile it, if the urandom method isn't sufficient straight-off.)
You may want to consider, for instance, generating larger random
numbers and doing some kind of translation on them - which is
fundamentally what the urandom/b64encode method is doing.

ChrisA

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performance of script to write very long lines of random chars gry <georgeryoung@gmail.com> - 2013-04-10 18:21 -0700
  Re: performance of script to write very long lines of random chars Chris Angelico <rosuav@gmail.com> - 2013-04-11 11:45 +1000
    Re: performance of script to write very long lines of random chars Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-11 05:33 +0000
      Re: performance of script to write very long lines of random chars Chris Angelico <rosuav@gmail.com> - 2013-04-11 15:53 +1000
  Re: performance of script to write very long lines of random chars Michael Torrie <torriem@gmail.com> - 2013-04-10 19:52 -0600
    Re: performance of script to write very long lines of random chars gry <georgeryoung@gmail.com> - 2013-04-10 19:40 -0700
      Re: performance of script to write very long lines of random chars Chris Angelico <rosuav@gmail.com> - 2013-04-11 13:14 +1000
  Re: performance of script to write very long lines of random chars MRAB <python@mrabarnett.plus.com> - 2013-04-11 04:09 +0100
  Re: performance of script to write very long lines of random chars Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-11 07:47 +0000
    Re: performance of script to write very long lines of random chars Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-04-11 10:47 +0100
      Re: performance of script to write very long lines of random chars Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-11 10:50 +0000
        Re: performance of script to write very long lines of random chars Robert Kern <robert.kern@gmail.com> - 2013-04-11 16:49 +0530
        Re: performance of script to write very long lines of random chars Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-04-11 13:05 +0100
        Re: performance of script to write very long lines of random chars Robert Kern <robert.kern@gmail.com> - 2013-04-11 19:06 +0530
        Re: performance of script to write very long lines of random chars Chris Angelico <rosuav@gmail.com> - 2013-04-11 23:56 +1000
  Re: performance of script to write very long lines of random chars Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-04-11 10:47 +0100

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