Re: running python 2 vs 3

References	(5 earlier) <87a9ckpq7y.fsf@elektro.pacujo.net> <mailman.8319.1395348268.18130.python-list@python.org> <87txasoaqi.fsf@elektro.pacujo.net> <532b8f0d$0$29994$c3e8da3$5496439d@news.astraweb.com> <roy-C004D1.21064220032014@news.panix.com>
Date	2014-03-21 13:18 +1100
Subject	Re: running python 2 vs 3
From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.8340.1395368318.18130.python-list@python.org> (permalink)

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On Fri, Mar 21, 2014 at 12:06 PM, Roy Smith <roy@panix.com> wrote:
> In article <532b8f0d$0$29994$c3e8da3$5496439d@news.astraweb.com>,
>  Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:
>
>> The rule of three applies here: anything you do in three different places
>> ought to be managed by a function.
>
> I prefer the rule of two :-)

The way I explain it is: Three is a rule of thumb. Sometimes it's
blatantly obvious at two, and other times you need four or five
similar pieces of code before you can see which part should become the
function. If the code's absolutely identical and reasonably
long/complex, then yes, two's all you need, but how often is that?
Usually it's similar, rather than congruent... err I mean identical.
That's where the third usage comes in. Or if it's maybe 2-3 lines,
used in two places, it doesn't necessarily need to be a function.
Again, a third usage is a strong hint that it should be broken out.

The rule doesn't say that anything that *isn't* in three places yet
should *not* be broken out. :)

ChrisA

Thread

running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 14:58 +0000
  Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 17:21 +0200
    Re: running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 16:00 +0000
      Re: running python 2 vs 3 Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-03-20 11:14 -0500
        Re: running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 17:10 +0000
          Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 04:30 +1100
          Re: running python 2 vs 3 Gary Herron <gary.herron@islandtraining.com> - 2014-03-20 10:45 -0700
          Re: running python 2 vs 3 John Gordon <gordon@panix.com> - 2014-03-20 19:07 +0000
            Re: running python 2 vs 3 Terry Reedy <tjreedy@udel.edu> - 2014-03-20 18:05 -0400
              Re: running python 2 vs 3 alex23 <wuwei23@gmail.com> - 2014-03-21 12:37 +1000
          Re: running python 2 vs 3 Michael Torrie <torriem@gmail.com> - 2014-03-20 15:44 -0600
    Re: running python 2 vs 3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-20 18:56 +0000
    Re: running python 2 vs 3 Eric Jacoboni <eric.jacoboni@gmail.com> - 2014-03-20 20:07 +0100
      Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 16:26 -0400
        Re: running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 21:16 +0000
        Re: running python 2 vs 3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-21 00:32 +0000
          Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 21:06 -0400
            Re: running python 2 vs 3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-21 03:16 +0000
              Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 14:34 +1100
          Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 12:10 +1100
          Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 21:20 -0400
    Re: running python 2 vs 3 Alan Meyer <ameyer2@yahoo.com> - 2014-03-20 15:53 -0400
      Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 22:08 +0200
        Re: running python 2 vs 3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-20 20:22 +0000
          Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 22:30 +0200
            Re: running python 2 vs 3 Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-03-20 15:43 -0500
            Re: running python 2 vs 3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-20 20:44 +0000
              Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 22:50 +0200
                Re: running python 2 vs 3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-20 21:36 +0000
                Re: running python 2 vs 3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-21 00:59 +0000
                Re: running python 2 vs 3 Roy Smith <roy@panix.com> - 2014-03-20 21:06 -0400
                Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 13:18 +1100
                Re: running python 2 vs 3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-21 09:40 +0000
                Re: running python 2 vs 3 alister <alister.nospam.ware@ntlworld.com> - 2014-03-21 12:09 +0000
                Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 12:15 +1100
            Re: running python 2 vs 3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-20 22:39 +0000
        Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 16:27 -0400
          Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 22:42 +0200
            Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 16:53 -0400
              Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 22:59 +0200
                Re: running python 2 vs 3 Chris Kaynor <ckaynor@zindagigames.com> - 2014-03-20 14:18 -0700
                Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 17:31 -0400
                Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-21 00:23 +0200
                Re: running python 2 vs 3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-20 22:42 +0000
                Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 10:18 +1100
                Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-21 07:49 +0200
                Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 16:54 +1100
                Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-21 08:08 +0200
                Re: running python 2 vs 3 Rustom Mody <rustompmody@gmail.com> - 2014-03-20 23:51 -0700
              Re: running python 2 vs 3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-21 00:37 +0000
                Re: running python 2 vs 3 Ethan Furman <ethan@stoneleaf.us> - 2014-03-20 18:23 -0700
              Re: running python 2 vs 3 Rustom Mody <rustompmody@gmail.com> - 2014-03-20 19:20 -0700
        Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 10:04 +1100
      Re: running python 2 vs 3 Mark H Harris <harrismh777@gmail.com> - 2014-03-20 15:10 -0500
        Re: running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 21:28 +0000
          Re: running python 2 vs 3 Mark H Harris <harrismh777@gmail.com> - 2014-03-20 16:46 -0500
          Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-21 00:17 +0200
          Re: running python 2 vs 3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-21 00:29 +0000
    Re: running python 2 vs 3 Dan Stromberg <drsalists@gmail.com> - 2014-03-20 13:38 -0700
      Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 22:46 +0200
  Re: running python 2 vs 3 Mark H Harris <harrismh777@gmail.com> - 2014-03-20 11:11 -0500
    Re: running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 17:23 +0000
      Re: running python 2 vs 3 Chris Angelico <rosuav@gmail.com> - 2014-03-21 04:29 +1100
        Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 19:45 +0200
      Re: running python 2 vs 3 Mark H Harris <harrismh777@gmail.com> - 2014-03-20 12:42 -0500
        Re: running python 2 vs 3 Marko Rauhamaa <marko@pacujo.net> - 2014-03-20 19:47 +0200
          Re: running python 2 vs 3 Ned Batchelder <ned@nedbatchelder.com> - 2014-03-20 14:45 -0400
          Re: running python 2 vs 3 Mark H Harris <harrismh777@gmail.com> - 2014-03-20 14:36 -0500
      Re: running python 2 vs 3 Terry Reedy <tjreedy@udel.edu> - 2014-03-20 17:52 -0400
        Re: running python 2 vs 3 notbob <notbob@nothome.com> - 2014-03-20 22:19 +0000

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