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Groups > comp.lang.python > #99025

Re: What is a function parameter =[] for?

From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Subject Re: What is a function parameter =[] for?
Date 2015-11-19 12:59 +1100
Message-ID <mailman.440.1447898362.16136.python-list@python.org> (permalink)
References <d9045bdd-a5d4-4c5c-9fd3-3d54f6b50862@googlegroups.com> <mailman.429.1447884751.16136.python-list@python.org> <n2j0k4$up4$1@dont-email.me> <mailman.432.1447888928.16136.python-list@python.org> <n2j98r$o9c$1@dont-email.me>

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On Thu, Nov 19, 2015 at 12:41 PM, BartC <bc@freeuk.com> wrote:
> On 18/11/2015 23:22, Chris Angelico wrote:
>> On the contrary, it is certain always to be that exact object.
>
> But, not the same value that appears as the default?

Nope. Mutable objects are never guaranteed to retain the same values.
That's kinda the point.

> Sorry, I didn't understand any of that. Let's try a simpler example like the
> OP's. There's this innocuous looking function that you are interested in
> calling:
>
>  def fn(a=[]):
>  #   print ("Function fn called with",a)
>  |   a.append(10)
>  |   return a
>
> It appends a value to its argument and returns the result.
>
> It looks like at first like, if called with no argument, it will return
> [10].

If you want to think of function defaults as being values, then yes.
But they're not. They're objects.

> But what it actually returns depends on the entire call history since the
> program started executing, something you probably have no knowledge of and
> no control over. So if fn has previously been called a million times with no
> argument, then after this call:
>
>  x=fn()
>
> x contains a list of a million tens, not one. I'd say most people would be
> rather surprised by that.

So if you don't want them to be surprised by that, don't use mutable
default arguments and expect them to have specific values.

> I suspect those same people (unless they are experts in the murky corners of
> the language) would expect:
>
>   x=fn()
>
> when fn specifies a default argument of [], to be the same as writing:
>
>   x=fn([])
>
> and not be dependent on fn's entire call history.

Tell me, do you expect these to do the same thing?

x = []
fn(x)
fn(x)
fn(x)

# or

fn([])
fn([])
fn([])

The distinction is exactly the same. If you can understand that the
first one constructs a single object and uses it three times, then you
should be able to understand that the function default is also
constructed once and used every time.

> Your solution of using:
>
>   def fn(a=None):
>
> is not really satisfactory. Partly because it now utilities two mechanisms
> for the default: first to get None, then some extra code to get []. But also
> it's no longer obvious how the function works and what the default is. At
> least, you can't tell from a glance at the start of the function that [] is
> the default.

This I do agree with. It's a bit clunky. It would be nice to be able to say:

def fn(a=`[]`):
    """If a is not passed, it will be a new empty list"""

and have it function the same as:

def fn(*args):
    a = args[0] if args else []

but currently there's no mechanism for it. (The example spelling I
gave is almost certainly not going to be used, due to the Tim Peters'
Monitor Grit argument, but something could probably be found.) It's a
sufficiently common situation that it would merit its own syntax. Want
to write up a PEP? All you need is a syntax that people can get
behind.

ChrisA

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Thread

What is a function parameter =[] for? fl <rxjwg98@gmail.com> - 2015-11-18 13:08 -0800
  Re: What is a function parameter =[] for? John Gordon <gordon@panix.com> - 2015-11-18 22:05 +0000
  Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-18 15:11 -0700
    Re: What is a function parameter =[] for? Grant Edwards <invalid@invalid.invalid> - 2015-11-18 22:33 +0000
    Re: What is a function parameter =[] for? fl <rxjwg98@gmail.com> - 2015-11-18 14:38 -0800
      Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-18 15:47 -0700
      Re: What is a function parameter =[] for? fl <rxjwg98@gmail.com> - 2015-11-18 14:48 -0800
    Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-18 23:14 +0000
      Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-19 10:22 +1100
        Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 01:41 +0000
          Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-19 12:59 +1100
            Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 11:41 +0000
              Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-19 22:58 +1100
              Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-19 23:45 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-19 08:42 -0700
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-22 14:58 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 13:38 +0100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 04:29 +1100
          Re: What is a function parameter =[] for? Ben Finney <ben+python@benfinney.id.au> - 2015-11-19 13:08 +1100
          Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-19 13:15 +1100
      Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-18 17:02 -0700
      Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-19 11:14 +1100
        Re: What is a function parameter =[] for? fl <rxjwg98@gmail.com> - 2015-11-18 16:34 -0800
          Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-18 17:52 -0700
          Re: What is a function parameter =[] for? MRAB <python@mrabarnett.plus.com> - 2015-11-19 01:02 +0000
          Re: What is a function parameter =[] for? Ben Finney <ben+python@benfinney.id.au> - 2015-11-19 12:26 +1100
          Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-19 22:38 +1100
      Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-19 23:19 +1100
        Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 13:19 +0000
          Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-20 00:45 +1100
          Re: What is a function parameter =[] for? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-11-19 09:05 -0500
          Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-20 03:01 +1100
            Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-20 04:30 +1100
            Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 17:30 +0000
              Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-20 04:45 +1100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 18:19 +0000
                Re: What is a function parameter =[] for? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-19 18:26 +0000
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 18:50 +0000
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-20 06:09 +1100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 19:48 +0000
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-20 06:58 +1100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-20 11:26 +1100
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-19 16:36 -0800
                Re: What is a function parameter =[] for? Laura Creighton <lac@openend.se> - 2015-11-20 02:00 +0100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-19 17:59 -0700
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-19 20:39 +0200
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-19 11:42 -0700
                Re: What is a function parameter =[] for? Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2015-11-19 18:44 +0000
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-20 06:19 +1100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-19 21:21 +0000
                Re: What is a function parameter =[] for? Michael Torrie <torriem@gmail.com> - 2015-11-19 15:55 -0700
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-20 00:11 +0000
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-19 16:27 -0800
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 14:43 +0100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 01:00 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 15:24 +0100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 01:34 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 16:01 +0100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 16:03 +0100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 16:12 +0100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 02:17 +1100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 04:54 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 16:46 +0100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 02:48 +1100
                Re: What is a function parameter =[] for? Random832 <random832@fastmail.com> - 2015-11-24 16:28 +0000
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 03:38 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 17:41 +0100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-24 09:56 -0700
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 18:32 +0100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-24 10:53 -0700
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-24 11:04 -0700
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 19:45 +0100
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-24 10:54 -0800
                Re: What is a function parameter =[] for? Random832 <random832@fastmail.com> - 2015-11-24 19:00 +0000
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 11:34 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-24 12:15 -0700
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-24 12:15 -0700
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 21:54 +0100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-24 21:14 +0000
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 22:25 +0100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 11:36 +1100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 11:56 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 10:56 +0100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-26 04:40 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 19:27 +0100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-26 11:10 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-25 13:39 -0700
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 22:05 +0100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-26 09:06 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-25 15:38 -0700
                Re: What is a function parameter =[] for? Alan Bawden <alan@csail.mit.edu> - 2015-11-25 21:08 -0500
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-26 13:25 +1100
                Re: What is a function parameter =[] for? Alan Bawden <alan@csail.mit.edu> - 2015-11-25 23:27 -0500
                Re: What is a function parameter =[] for? Dave Farrance <df@see.replyto.invalid> - 2015-11-26 10:34 +0000
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 12:58 +0200
                Re: What is a function parameter =[] for? Dave Farrance <df@see.replyto.invalid> - 2015-11-26 11:12 +0000
                Object identity has no necessary connection to memory location (was: What is a function parameter =[] for?) Ben Finney <ben+python@benfinney.id.au> - 2015-11-26 22:24 +1100
                Re: Object identity has no necessary connection to memory location (was: What is a function parameter =[] for?) Dave Farrance <df@see.replyto.invalid> - 2015-11-26 11:50 +0000
                Re: Object identity has no necessary connection to memory location Ben Finney <ben+python@benfinney.id.au> - 2015-11-27 07:00 +1100
                Re: Object identity has no necessary connection to memory location Steven D'Aprano <steve@pearwood.info> - 2015-11-27 13:17 +1100
                Re: Object identity has no necessary connection to memory location Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-26 21:44 +0000
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-26 22:24 +1100
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-26 13:27 +0200
                Re: Object identity has no necessary connection to memory location (was: What is a function parameter =[] for?) Chris Angelico <rosuav@gmail.com> - 2015-11-26 22:49 +1100
                Re: Object identity has no necessary connection to memory location Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-26 13:04 +0100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-27 12:34 +1100
                Re: What is a function parameter =[] for? Ben Finney <ben+python@benfinney.id.au> - 2015-11-27 12:40 +1100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-27 13:44 +1100
                Re: What is a function parameter =[] for? MRAB <python@mrabarnett.plus.com> - 2015-11-27 02:56 +0000
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-27 23:57 +1100
                Re: What is a function parameter =[] for? Laura Creighton <lac@openend.se> - 2015-11-27 14:24 +0100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-28 00:29 +1100
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-27 14:06 +1100
                Re: What is a function parameter =[] for? Ben Finney <ben+python@benfinney.id.au> - 2015-11-27 15:56 +1100
                Re: What is a function parameter =[] for? Random832 <random832@fastmail.com> - 2015-11-26 23:33 -0500
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-25 19:46 -0700
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-26 14:02 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-26 09:15 +0100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-24 14:33 -0700
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 09:09 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-19 12:25 -0700
              Re: What is a function parameter =[] for? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-19 18:20 +0000
              Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-20 12:05 +1100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-20 11:59 +0000
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-20 04:12 -0800
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-20 12:39 +0000
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-21 00:04 +1100
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-20 05:30 -0800
                Re: What is a function parameter =[] for? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-11-20 08:34 -0500
                Re: What is a function parameter =[] for? Random832 <random832@fastmail.com> - 2015-11-20 14:32 +0000
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-20 09:18 -0700
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-22 23:01 +1100
                Re: What is a function parameter =[] for? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-11-23 12:30 +1300
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 15:38 +0100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 15:34 +0100
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-24 06:50 -0800
                Re: What is a function parameter =[] for? Terry Reedy <tjreedy@udel.edu> - 2015-11-24 12:46 -0500
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 19:27 +0100
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-20 14:28 +0200
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-20 12:53 +0000
                Re: What is a function parameter =[] for? Random832 <random832@fastmail.com> - 2015-11-20 14:35 +0000
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-22 21:06 +1100
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-22 14:35 +0200
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-20 09:16 -0700
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-20 18:31 +0200
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-21 03:37 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-20 09:39 -0700
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-21 03:24 +1100
                Re: What is a function parameter =[] for? Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-20 09:29 -0700
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-20 18:41 +0200
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-21 03:36 +1100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-22 14:43 +1100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-22 13:21 +0000
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-22 14:28 +0000
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-23 10:44 +1100
                Re: What is a function parameter =[] for? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-23 00:04 +0000
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-23 00:37 +0000
                Re: What is a function parameter =[] for? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-23 11:32 +0000
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-23 04:05 -0800
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-23 14:23 +0200
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-23 11:20 +1100
                Re: What is a function parameter =[] for? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-11-23 12:43 +1300
                Re: What is a function parameter =[] for? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-11-23 18:47 +1100
                Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-23 10:40 +0000
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-24 00:58 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 15:58 +0100
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 04:56 +1100
                Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 15:18 +0100
              Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 14:48 +0100
      Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 12:36 +0100
      Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-24 23:07 +1100
      Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 13:48 +0100
        Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-24 14:57 +0200
          Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-24 06:18 -0800
            Re: What is a function parameter =[] for? BartC <bc@freeuk.com> - 2015-11-24 14:43 +0000
              Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-25 01:54 +1100
            Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-24 16:10 +0100
              Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-24 07:27 -0800
                Re: What is a function parameter =[] for? Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2015-11-24 17:25 +0000
                Re: What is a function parameter =[] for? Ned Batchelder <ned@nedbatchelder.com> - 2015-11-24 09:35 -0800
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-24 20:13 +0200
                Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 05:33 +1100
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-24 21:17 +0200
            Re: What is a function parameter =[] for? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-11-24 11:27 -0500
            Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 11:39 +1100
              Re: What is a function parameter =[] for? Laura Creighton <lac@openend.se> - 2015-11-25 01:55 +0100
              A name refers to an object, an object has a value, equality compares values (was: What is a function parameter =[] for?) Ben Finney <ben+python@benfinney.id.au> - 2015-11-25 13:17 +1100
                Re: A name refers to an object, an object has a value, equality compares values Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 08:44 +0200
                Re: A name refers to an object, an object has a value, equality compares values Chris Angelico <rosuav@gmail.com> - 2015-11-25 19:27 +1100
              Re: What is a function parameter =[] for? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-25 10:36 +0100
                Re: What is a function parameter =[] for? Jussi Piitulainen <harvest@should.be.invalid> - 2015-11-25 13:39 +0200
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 14:48 +0200
                Re: What is a function parameter =[] for? Chris Angelico <rosuav@gmail.com> - 2015-11-26 00:50 +1100
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 16:08 +0200
                Re: What is a function parameter =[] for? Jussi Piitulainen <harvest@should.be.invalid> - 2015-11-25 17:13 +0200
                Re: What is a function parameter =[] for? Marko Rauhamaa <marko@pacujo.net> - 2015-11-25 18:44 +0200
                Re: What is a function parameter =[] for? Jussi Piitulainen <harvest@should.be.invalid> - 2015-11-25 20:30 +0200
          Re: What is a function parameter =[] for? Steven D'Aprano <steve@pearwood.info> - 2015-11-25 03:11 +1100

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