Re: Suggestion: make sequence and map interfaces more similar

From	Antoon Pardon <antoon.pardon@rece.vub.ac.be>
Newsgroups	comp.lang.python
Subject	Re: Suggestion: make sequence and map interfaces more similar
Date	2016-03-30 10:55 +0200
Message-ID	<mailman.185.1459328147.28225.python-list@python.org> (permalink)
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Op 30-03-16 om 07:43 schreef Steven D'Aprano:
> Yes, we're all very impressed that you spotted the trivial and obvious 
> loophole that changing a key:value will change the key:value that you just 
> changed *wink* but that doesn't really move the discussion anywhere.
>
> This is not an argument about dicts being mutable, because clearly they 
> aren't. This is an argument about key:value pairs being stable. "Stable" 
> doesn't mean "immutable". If you change the value associated with a key 
> directly, then it will change. That's the whole point. But if you change 
> *one* key, the relationship between *other* keys and their values shouldn't 
> change.
>
> Given a surjection (many-to-one mapping) between keys and values in a 
> mapping, we expect that changing the mapping of one key will not affect 
> other keys. To be pedantic, by "change" I mean deleting the key (and, if 
> necessary, value) or reassigning a new value to the key. To be even more 
> pedantic, mutations to the value *do not count*.

I don't expect that generally. Sure there are specific mapping implementations
for which this is true, but I see no reason to limit the word mapping only to
those kind of data-types.

What I want from a mapping is that it gives me the correct correspondence between
a key and a value for the application I am using it for. If that means a "stable"
mapping I'll limit the operations on that mapping as to keep it that way. Which
in a number of case can be perfectly done with python-lists.

So generally there is no reason to limit the word "mapping" to stable mappings.

-- 
Antoon Pardon

Thread

Re: Suggestion: make sequence and map interfaces more similar "Marco S." <mail.python.org@marco.sulla.e4ward.com> - 2016-03-27 20:01 +0200
  Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-28 12:05 +1100
    Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-29 16:08 +0200
    Re: Suggestion: make sequence and map interfaces more similar Chris Angelico <rosuav@gmail.com> - 2016-03-30 01:31 +1100
    Re: Suggestion: make sequence and map interfaces more similar Marco Sulla <mail.python.org@marco.sulla.e4ward.com> - 2016-03-30 00:29 +0200
    Re: Suggestion: make sequence and map interfaces more similar Terry Reedy <tjreedy@udel.edu> - 2016-03-29 20:55 -0400
    Re: Suggestion: make sequence and map interfaces more similar Chris Angelico <rosuav@gmail.com> - 2016-03-30 11:56 +1100
    Re: Suggestion: make sequence and map interfaces more similar Random832 <random832@fastmail.com> - 2016-03-29 23:38 -0400
      Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-30 16:43 +1100
        Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-30 16:57 +1100
        Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 10:12 +0300
          Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-30 21:17 +1100
            Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 13:28 +0300
              Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-30 12:34 +0200
                Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 13:57 +0300
              Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-30 23:22 +1100
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-30 15:12 +0200
                Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-31 02:56 +1100
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-30 21:07 +0200
                Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-31 13:40 +1100
                Re: Suggestion: make sequence and map interfaces more similar Paul Rubin <no.email@nospam.invalid> - 2016-03-30 19:45 -0700
                Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-31 17:45 +1100
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-31 09:52 +0200
                Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-31 21:36 +1100
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-31 12:51 +0200
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-31 13:22 +0200
                Re: Suggestion: make sequence and map interfaces more similar Chris Angelico <rosuav@gmail.com> - 2016-03-31 22:57 +1100
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-31 15:36 +0300
                Re: Suggestion: make sequence and map interfaces more similar Chris Angelico <rosuav@gmail.com> - 2016-03-31 23:48 +1100
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-31 17:02 +0300
                Re: Suggestion: make sequence and map interfaces more similar Michael Selik <michael.selik@gmail.com> - 2016-04-01 04:19 -0400
                Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-31 15:55 +0300
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-31 17:19 +0300
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-31 15:08 +0200
                Re: Suggestion: make sequence and map interfaces more similar Rustom Mody <rustompmody@gmail.com> - 2016-03-31 06:42 -0700
                Re: Suggestion: make sequence and map interfaces more similar Chris Angelico <rosuav@gmail.com> - 2016-04-01 00:11 +1100
                Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-31 14:17 +0100
                Re: Suggestion: make sequence and map interfaces more similar Random832 <random832@fastmail.com> - 2016-03-31 09:27 -0400
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-31 17:13 +0300
                Re: Suggestion: make sequence and map interfaces more similar Terry Reedy <tjreedy@udel.edu> - 2016-03-31 13:41 -0400
                Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-31 15:12 +0100
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-04-01 09:59 +0200
                Re: Suggestion: make sequence and map interfaces more similar Tim Golden <mail@timgolden.me.uk> - 2016-04-01 09:27 +0100
                Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-04-01 21:38 +1100
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 13:50 +0300
                Re: Suggestion: make sequence and map interfaces more similar Rustom Mody <rustompmody@gmail.com> - 2016-04-01 07:41 -0700
                Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-04-01 10:04 +0100
                Re: Suggestion: make sequence and map interfaces more similar Marco Sulla <mail.python.org@marco.sulla.e4ward.com> - 2016-03-30 21:35 +0200
                Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-30 21:31 +0100
            Re: Suggestion: make sequence and map interfaces more similar Manolo Martínez <manolo@austrohungaro.com> - 2016-03-30 12:26 +0200
              Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 13:40 +0300
                Re: Suggestion: make sequence and map interfaces more similar Manolo Martínez <manolo@austrohungaro.com> - 2016-03-30 12:50 +0200
                Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 14:21 +0300
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-30 14:44 +0300
                Re: Suggestion: make sequence and map interfaces more similar Manolo Martínez <manolo@austrohungaro.com> - 2016-03-30 14:29 +0200
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-30 15:55 +0300
                Re: Suggestion: make sequence and map interfaces more similar Manolo Martínez <manolo@austrohungaro.com> - 2016-03-30 15:13 +0200
                Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-30 23:27 +1100
                Re: Suggestion: make sequence and map interfaces more similar Marko Rauhamaa <marko@pacujo.net> - 2016-03-30 15:48 +0300
                Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 17:38 +0300
                Re: Suggestion: make sequence and map interfaces more similar Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-30 17:25 +0300
        Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-30 10:55 +0200
        Re: Suggestion: make sequence and map interfaces more similar Random832 <random832@fastmail.com> - 2016-03-30 08:50 -0400
          Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-31 03:02 +1100
            Re: Suggestion: make sequence and map interfaces more similar Random832 <random832@fastmail.com> - 2016-03-30 12:52 -0400
              Re: Suggestion: make sequence and map interfaces more similar Steven D'Aprano <steve@pearwood.info> - 2016-03-31 13:44 +1100
                Re: Suggestion: make sequence and map interfaces more similar Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2016-03-31 10:04 +0200
                Re: Suggestion: make sequence and map interfaces more similar Marco Sulla <mail.python.org@marco.sulla.e4ward.com> - 2016-03-31 13:58 +0200
                Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-31 13:30 +0100
                Re: Suggestion: make sequence and map interfaces more similar Marco Sulla <mail.python.org@marco.sulla.e4ward.com> - 2016-03-31 14:49 +0200
                Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-31 14:14 +0100
            Re: Suggestion: make sequence and map interfaces more similar Marco Sulla <mail.python.org@marco.sulla.e4ward.com> - 2016-03-30 22:00 +0200
            Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-30 21:36 +0100
    Re: Suggestion: make sequence and map interfaces more similar Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-30 08:03 +0100

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