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Re: "monty" < "python"

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Date Thu, 21 Mar 2013 08:02:53 +1100
Subject Re: "monty" < "python"
From Tim Delaney <tim.delaney@aptare.com>
To Python-List <python-list@python.org>
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On 21 March 2013 06:40, jmfauth <wxjmfauth@gmail.com> wrote:

> ----
> [snip usual rant from jmf]


Franz, please pay no attention to jmf. He has become obsessed with a single
small regression in Python 3.3 in performance with how strings perform in a
very small domain that rarely shows up in practice (although as he has
demonstrated, it is easy to create a microbenchmark that makes it appear to
be much worse than it is).

The regression is a consequence of the decision in Python 3.3 to
*correctly* support the full range of Unicode characters whilst also
reducing the required memory where possible. In the vast majority of cases
this is a performance *improvement*. It is only "optimised for the ascii
user" in the sense that in the Unicode standard the pre-existing ASCII
characters only require 1 byte per code point and hence can be stored in
less memory than most other Unicode code points. The possible character
widths are 1, 2 and 4 bytes.

The actual regression occurs when concatentating/replacing/etc a character
to a string that is wider than any other character currently in the string.
In this situation the new string needs to be widened (increase the number
of bytes used by every character) which is a much more expensive operation
than simply creating a new string (which is what would happen if the
character was the same size or smaller).

It has been acknowledged as a real regression, but he keeps hijacking every
thread where strings are mentioned to harp on about it. He has shown no
inclination to attempt to *fix* the regression and is rapidly coming to be
regarded as a troll by most participants in this list.

Tim Delaney

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Thread

"monty" < "python" franzferdinand <melo.dumoulin@hotmail.com> - 2013-03-20 06:33 -0700
  Re: "monty" < "python" Jan Oelze <jan@codein.is> - 2013-03-20 14:38 +0100
    Re: "monty" < "python" Roy Smith <roy@panix.com> - 2013-03-20 09:58 -0400
      Re: "monty" < "python" franzferdinand <melo.dumoulin@hotmail.com> - 2013-03-20 07:03 -0700
        Re: "monty" < "python" Terry Reedy <tjreedy@udel.edu> - 2013-03-21 04:08 -0400
          Re: "monty" < "python" Roy Smith <roy@panix.com> - 2013-03-21 08:45 -0400
            Re: "monty" < "python" Chris Angelico <rosuav@gmail.com> - 2013-03-21 23:55 +1100
            Re: "monty" < "python" Wayne Werner <wayne@waynewerner.com> - 2013-03-21 07:56 -0500
            Re: "monty" < "python" Dave Angel <davea@davea.name> - 2013-03-21 09:02 -0400
  Re: "monty" < "python" "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-03-20 13:40 +0000
  Re: "monty" < "python" Ian Foote <ian@feete.org> - 2013-03-20 14:17 +0000
  Re: "monty" < "python" Jan Oelze <jan@codein.is> - 2013-03-20 15:23 +0100
  Re: "monty" < "python" Grant Edwards <invalid@invalid.invalid> - 2013-03-20 16:04 +0000
    Re: "monty" < "python" jmfauth <wxjmfauth@gmail.com> - 2013-03-20 12:40 -0700
      Re: "monty" < "python" Tim Delaney <tim.delaney@aptare.com> - 2013-03-21 08:02 +1100
        Re: "monty" < "python" jmfauth <wxjmfauth@gmail.com> - 2013-03-23 02:24 -0700
          Re: "monty" < "python" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-03-23 16:17 +0000
            Re: "monty" < "python" jmfauth <wxjmfauth@gmail.com> - 2013-03-24 06:31 -0700
              Re: "monty" < "python" Chris Angelico <rosuav@gmail.com> - 2013-03-25 00:44 +1100
              Re: "monty" < "python" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-03-24 14:08 +0000
      Re: "monty" < "python" Michael Torrie <torriem@gmail.com> - 2013-03-20 19:41 -0600
      Re: "monty" < "python" Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-03-21 02:52 +0000
      Re: "monty" < "python" rusi <rustompmody@gmail.com> - 2013-03-20 20:12 -0700
        Vowels [was Re: "monty" < "python"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-03-21 04:28 +0000
          Re: Vowels [was Re: "monty" < "python"] Larry Hudson <orgnut@yahoo.com> - 2013-03-20 23:26 -0700
            Re: Vowels [was Re: "monty" < "python"] David H Wild <dhwild@talktalk.net> - 2013-03-21 09:36 +0000
              Re: Vowels [was Re: "monty" < "python"] Chris Angelico <rosuav@gmail.com> - 2013-03-21 21:09 +1100
                Re: Vowels [was Re: "monty" < "python"] Peter Pearson <ppearson@nowhere.invalid> - 2013-03-21 21:52 +0000
                Re: Vowels [was Re: "monty" < "python"] Chris Angelico <rosuav@gmail.com> - 2013-03-22 08:59 +1100
              Re: Vowels [was Re: "monty" < "python"] istjanichtzufassen@gmail.com - 2013-03-21 06:26 -0700
                Re: Vowels [was Re: "monty" < "python"] Chris Angelico <rosuav@gmail.com> - 2013-03-22 00:38 +1100
          Re: Vowels [was Re: "monty" < "python"] Grant Edwards <invalid@invalid.invalid> - 2013-03-21 17:31 +0000
            Re: Vowels [was Re: "monty" < "python"] Terry Reedy <tjreedy@udel.edu> - 2013-03-21 19:05 -0400
              Re: Vowels [was Re: "monty" < "python"] Roy Smith <roy@panix.com> - 2013-03-21 20:09 -0400
              Re: Vowels [was Re: "monty" < "python"] Grant Edwards <invalid@invalid.invalid> - 2013-03-22 14:14 +0000
            Re: Vowels [was Re: "monty" < "python"] Stefan Behnel <stefan_ml@behnel.de> - 2013-03-24 15:25 +0100
              Re: Vowels [was Re: "monty" < "python"] rusi <rustompmody@gmail.com> - 2013-03-24 08:04 -0700
            Re: Vowels [was Re: "monty" < "python"] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-03-24 16:12 +0000
        Re: "monty" < "python" jmfauth <wxjmfauth@gmail.com> - 2013-03-23 02:23 -0700
          Re: "monty" < "python" Chris Angelico <rosuav@gmail.com> - 2013-03-23 20:45 +1100
          Re: "monty" < "python" Chris Angelico <rosuav@gmail.com> - 2013-03-23 20:56 +1100
          Re: "monty" < "python" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-03-23 16:06 +0000

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