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Re: what does 'a=b=c=[]' do

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rusi wrote:
> On Dec 23, 7:10 am, alex23 <wuwe...@gmail.com> wrote:
>> On Dec 22, 6:51 pm, Rolf Camps <r...@roce.be> wrote:
>>
>>> I'm afraid it's dangerous to encourage the use of '[]' as assignment to
>>> a parameter in a function definition. If you use the function several
>>> times 'default' always points to the same list.
 >>
>> I appreciate the concern, but adding a default argument guard would
>> not only obscure the code. It's irrelevant, as you recognise, because
>> no matter what, it's going to make copies of the default argument.
>>
>> You know what the say about foolish consistencies :)
> 
> Programming languages can have bugs as much as programs can.
> A classic example is the precedence table of C which Kernighan or
> Ritchie (dont remember which) admitted was wrong.
> 
> Likewise function arguments that default to mutable entities is a
> known gotcha of python which is best treated as a bug in python. It
> should be avoided with the suitable additional circumspection that a
> language bug deserves over a program bug.

That is the most ridiculous thing I have heard in a while.  Mutable 
default arguments are *not* a bug in Python.

Reminds me of a bug report a couple years back claiming multiple 
inheritence was a bug and asking it to be removed.

~Ethan~

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what does 'a=b=c=[]' do Eric <einazaki668@yahoo.com> - 2011-12-21 14:25 -0800
  Re: what does 'a=b=c=[]' do Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2011-12-21 18:20 -0500
    Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-21 23:48 +0000
      Re: what does 'a=b=c=[]' do Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-24 19:41 +0100
        Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-25 13:16 +0000
    Re: what does 'a=b=c=[]' do Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-24 19:45 +0100
  Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-21 23:44 +0000
    Re: what does 'a=b=c=[]' do Eric <einazaki668@yahoo.com> - 2011-12-22 20:27 -0800
  Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-21 16:50 -0800
    Re: what does 'a=b=c=[]' do Rolf Camps <rolf@roce.be> - 2011-12-22 09:51 +0100
      Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-22 18:10 -0800
        Re: what does 'a=b=c=[]' do Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-22 19:59 -0700
          Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-22 19:40 -0800
            Re: what does 'a=b=c=[]' do Chris Angelico <rosuav@gmail.com> - 2011-12-23 15:25 +1100
            Re: what does 'a=b=c=[]' do Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-22 22:22 -0700
              Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-22 22:00 -0800
        Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 00:38 -0800
          Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 09:39 +0000
            Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 02:22 -0800
              Re: what does 'a=b=c=[]' do Robert Kern <robert.kern@gmail.com> - 2011-12-23 13:10 +0000
                Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 05:23 -0800
                Re: what does 'a=b=c=[]' do Robert Kern <robert.kern@gmail.com> - 2011-12-23 13:53 +0000
                Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 06:57 -0800
                Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 15:33 +0000
                Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 07:59 -0800
          Re: what does 'a=b=c=[]' do Ethan Furman <ethan@stoneleaf.us> - 2011-12-23 00:49 -0800
          Re: what does 'a=b=c=[]' do Chris Angelico <rosuav@gmail.com> - 2011-12-23 20:59 +1100
            Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 02:31 -0800
              Timeout when calling COM objects on Windows Wong Wah Meng-R32813 <r32813@freescale.com> - 2011-12-23 11:20 +0000
              Re: what does 'a=b=c=[]' do Michael Torrie <torriem@gmail.com> - 2011-12-23 10:23 -0700
            Re: what does 'a=b=c=[]' do Neil Cerutti <neilc@norwich.edu> - 2011-12-23 13:10 +0000
              Re: what does 'a=b=c=[]' do Neil Cerutti <neilc@norwich.edu> - 2011-12-23 13:13 +0000
                Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 15:49 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Chris Angelico <rosuav@gmail.com> - 2011-12-24 02:55 +1100
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 22:32 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Chris Angelico <rosuav@gmail.com> - 2011-12-24 09:50 +1100
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-24 08:11 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Roy Smith <roy@panix.com> - 2011-12-23 11:15 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 05:43 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Mel Wilson <mwilson@the-wire.com> - 2011-12-23 11:27 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 05:52 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Neil Cerutti <neilc@norwich.edu> - 2011-12-23 17:03 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-24 08:25 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 06:08 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Devin Jeanpierre <jeanpierreda@gmail.com> - 2011-12-24 18:25 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 16:10 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Devin Jeanpierre <jeanpierreda@gmail.com> - 2011-12-24 19:32 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] rusi <rustompmody@gmail.com> - 2011-12-24 19:22 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Lie Ryan <lie.1296@gmail.com> - 2011-12-25 15:12 +1100
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Devin Jeanpierre <jeanpierreda@gmail.com> - 2011-12-23 19:24 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-24 08:26 +0000
        Re: what does 'a=b=c=[]' do Ethan Furman <ethan@stoneleaf.us> - 2011-12-23 00:38 -0800
    Re: what does 'a=b=c=[]' do Ethan Furman <ethan@stoneleaf.us> - 2011-12-22 05:20 -0800
    Re: what does 'a=b=c=[]' do Eric <einazaki668@yahoo.com> - 2011-12-22 19:46 -0800
  Re: what does 'a=b=c=[]' do Lie Ryan <lie.1296@gmail.com> - 2011-12-24 21:30 +1100
  Re: what does 'a=b=c=[]' do Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-24 19:49 +0100

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