Re: Coolest Python recipe of all time

From	Raymond Hettinger <python@rcn.com>
Newsgroups	comp.lang.python
Subject	Re: Coolest Python recipe of all time
Date	2011-05-03 15:19 -0700
Organization	http://groups.google.com
Message-ID	<b8f9d60a-4f8e-45fd-ba10-0092ac9d75d8@18g2000prd.googlegroups.com> (permalink)
References	(2 earlier) <mailman.1079.1304369965.9059.python-list@python.org> <018ur6da31iv7us9gm4dpgl7tfl0i6snb2@4ax.com> <ipo2df$14c$1@dough.gmane.org> <ipo5l4$fdn$1@dough.gmane.org> <mailman.1099.1304403854.9059.python-list@python.org>

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On May 2, 11:23 pm, Stefan Behnel <stefan...@behnel.de> wrote:
> Terry Reedy, 03.05.2011 08:00:
>
> > On 5/3/2011 1:04 AM, Stefan Behnel wrote:
>
> >> The bad thing about this recipe is that it requires quite a bit of
> >> background knowledge in order to infer that the code the developer is
> >> looking at is actually correct.
>
> > The main math knowledge needed is the trivial fact that if a*x + b = 0,
> > then x = -b/a. The other math knowledge needed is that complex numbers add
> > componentwise. The trick is that replacing x with j and evaluating
> > therefore causes (in Python) all the coefficients of x (now j) to be added
> > together separately from all the constant terms to reduce the linear
> > equation to a*x+b (= 0 implied).
>
> As your above paragraph proves, it's the kind of implementation that
> requires three lines of executing code and at least 6 lines of additional
> comment. Hopefully accompanied by an excuse of the developer.

If you found nothing educational, interesting, or amusing about the
three-line linear equation solver, then you're *really* going to hate
this one:

  http://groups.google.com/group/comp.lang.python/browse_frm/thread/e46de4596e93188b/


Raymond
@raymondh

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Thread

Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-02 10:33 -0700
  Re: Coolest Python recipe of all time David Monaghan <monaghand.david@gmail.com> - 2011-05-02 21:48 +0100
    Re: Coolest Python recipe of all time Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-02 14:58 -0600
      Re: Coolest Python recipe of all time David Monaghan <monaghand.david@gmail.com> - 2011-05-02 22:45 +0100
        Re: Coolest Python recipe of all time Stefan Behnel <stefan_ml@behnel.de> - 2011-05-03 07:04 +0200
          Re: Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-03 09:43 -0700
            Re: Coolest Python recipe of all time Chris Angelico <rosuav@gmail.com> - 2011-05-04 07:54 +1000
            Re: Coolest Python recipe of all time Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-03 16:10 -0600
        Re: Coolest Python recipe of all time Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-02 23:17 -0600
        Re: Coolest Python recipe of all time Terry Reedy <tjreedy@udel.edu> - 2011-05-03 02:00 -0400
          Re: Coolest Python recipe of all time Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-05-03 18:29 +1200
            Re: Coolest Python recipe of all time Terry Reedy <tjreedy@udel.edu> - 2011-05-03 11:49 -0400
            Re: Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-03 09:32 -0700
            Re: Coolest Python recipe of all time geremy condra <debatem1@gmail.com> - 2011-05-03 09:51 -0700
        Re: Coolest Python recipe of all time Stefan Behnel <stefan_ml@behnel.de> - 2011-05-03 08:23 +0200
          Re: Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-03 15:19 -0700
  Re: Coolest Python recipe of all time Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-06 16:59 +0000
    Re: Coolest Python recipe of all time geremy condra <debatem1@gmail.com> - 2011-05-06 10:43 -0700
    Re: Coolest Python recipe of all time Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-06 12:36 -0600
      Re: Coolest Python recipe of all time Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-07 08:29 +0000
        Re: Coolest Python recipe of all time Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-07 08:54 -0600
        Re: Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-07 14:02 -0700
    Re: Coolest Python recipe of all time Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-06 13:38 -0600
    Re: Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-06 12:58 -0700
  RE: Coolest Python recipe of all time Trent Nelson <trent@snakebite.org> - 2011-05-09 02:31 -0700
    Re: Coolest Python recipe of all time Raymond Hettinger <python@rcn.com> - 2011-05-09 14:10 -0700

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