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Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?)

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From Antoon Pardon <antoon.pardon@rece.vub.ac.be>
Newsgroups comp.lang.python
Subject Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?)
Date Wed, 25 Nov 2015 09:14:48 +0100
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Op 20-11-15 om 01:33 schreef Steven D'Aprano:
> On Fri, 20 Nov 2015 07:57 am, Marko Rauhamaa wrote:
>
>> Laura Creighton <lac@openend.se>:
>>
>>> My experience says that the people who are confused want lists to
>>> behave like tuples. period. i.e. they don't want lists to be mutable.
>> I think it's simpler than that. When you have:
>>
>>    def f(x=[]):
>>        y = []
>>
>> the first [] is evaluated when "def" is executed, while the latter [] is
>> evaluated whenever "f" is executed. It's easy to be confused.
> It shouldn't be. The function declaration 
>
>     def f(x=[]):
>
> is executed only once. The function body, conveniently indented to make it
> stand out:
>
>         y = []
>
> is executed every time you call the function. 

What exactly is your point? People's confusions don't disappear
because you as an expert have a good understanding of what is
going on and so are no longer confused.

Some aspects in the langauage are easily grasped and other
aspects tend to create confusion. I see nothing wrong with
people trying to point out what the cause of this confusion
could be. You arguing that people shouldn't be confused is
not helping.

-- 
Antoon.

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Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Laura Creighton <lac@openend.se> - 2015-11-19 21:18 +0100
  Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-19 22:57 +0200
    Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Laura Creighton <lac@openend.se> - 2015-11-19 23:41 +0100
      Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-20 14:00 +0000
    Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-20 11:33 +1100
      Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 09:14 +0100
        Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-25 21:52 +1100
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 13:25 +0100
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 13:20 +0000
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ned Batchelder <ned@nedbatchelder.com> - 2015-11-25 07:13 -0800
              Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Laura Creighton <lac@openend.se> - 2015-11-25 16:59 +0100
                Multiplication [was Re: Late-binding of function defaults] Steven D'Aprano <steve@pearwood.info> - 2015-11-26 05:09 +1100
                Re: Multiplication [was Re: Late-binding of function defaults] Laura Creighton <lac@openend.se> - 2015-11-25 19:45 +0100
                Re: Multiplication [was Re: Late-binding of function defaults] Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 23:04 +0200
              Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Arie van Wingerden <xapwing@gmail.com> - 2015-11-25 17:12 +0100
              Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 03:29 +1100
              Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 17:18 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-25 11:03 -0700
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 18:48 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-25 20:50 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 21:56 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 00:16 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 22:41 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-26 11:31 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-26 01:23 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ned Batchelder <ned@nedbatchelder.com> - 2015-11-25 17:52 -0800
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ben Finney <ben+python@benfinney.id.au> - 2015-11-26 16:08 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-26 06:39 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-26 09:31 +0100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-26 12:53 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-27 00:15 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-26 14:40 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) MRAB <python@mrabarnett.plus.com> - 2015-11-26 16:14 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-26 22:27 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-27 10:07 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Random832 <random832@fastmail.com> - 2015-11-26 19:15 -0500
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-27 11:48 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) MRAB <python@mrabarnett.plus.com> - 2015-11-27 01:15 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) MRAB <python@mrabarnett.plus.com> - 2015-11-26 16:16 +0000
                Re: Late-binding of function defaults (was Re: What is a function   parameter =[] for?) Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-11-27 10:48 +1300
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-27 12:46 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-27 02:01 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 08:41 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-27 12:09 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-27 10:31 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-27 13:30 +0200
              Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ben Finney <ben+python@benfinney.id.au> - 2015-11-26 06:57 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 23:00 +0200
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Emile van Sebille <emile@fenx.com> - 2015-11-25 10:56 -0800
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-26 13:01 +1100
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 00:24 +1100
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 15:17 +0100
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Emile van Sebille <emile@fenx.com> - 2015-11-25 10:51 -0800
      Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-25 19:32 +1100
        Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 10:43 +0200
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-25 21:58 +1100
        Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 12:35 +0000
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 15:06 +0200
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 13:37 +0000
              Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 15:53 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) BartC <bc@freeuk.com> - 2015-11-25 14:34 +0000
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-11-25 13:32 -0500
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-26 11:53 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 08:52 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 18:14 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 10:27 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 19:34 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 12:54 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 22:04 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 13:23 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 22:35 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 14:03 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-27 12:43 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-26 09:45 +0100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-11-27 10:20 +1300
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 23:36 +0200
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Steven D'Aprano <steve@pearwood.info> - 2015-11-27 12:23 +1100
                Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-26 11:17 +0000
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 00:44 +1100
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ben Finney <ben+python@benfinney.id.au> - 2015-11-26 06:55 +1100
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Random832 <random832@fastmail.com> - 2015-11-26 00:52 +0000
            Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-25 20:01 -0700
            Semantics of collection types (was: Late-binding of function defaults (was Re: What is a function parameter =[] for?)) Ben Finney <ben+python@benfinney.id.au> - 2015-11-26 16:04 +1100
          Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 00:35 +1100
        Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Larry Hudson <orgnut@yahoo.com> - 2015-11-25 22:44 -0800
      Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 10:13 +0100

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