What does it mean for Python to have “constants”? (was: variable scope of class objects)

From	Ben Finney <ben+python@benfinney.id.au>
Subject	What does it mean for Python to have “constants”? (was: variable scope of class objects)
Date	2015-10-21 11:27 +1100
References	<q3da2bplpbt2njpoojie8ogfo7te63lhn2@4ax.com> <n04m96$tvd$1@speranza.aioe.org> <9ocd2btlkq7kp3margtn4sj3mehd7bpimm@4ax.com> <kqkd2b9gkcsdade6jlev55jpbqo7h1k4n5@4ax.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.65.1445387285.878.python-list@python.org> (permalink)

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Dennis Lee Bieber <wlfraed@ix.netcom.com> writes:

> (Python does not have anything that one might consider a true constant
> -- other than the language defined singletons: None, and maybe by now
> True and False).

Python now deals with those by making the names keywords::

    >>> True = object()
      File "<stdin>", line 1
    SyntaxError: can't assign to keyword
    >>> False = object()
      File "<stdin>", line 1
    SyntaxError: can't assign to keyword
    >>> None = object()
      File "<stdin>", line 1
    SyntaxError: can't assign to keyword

which seems to rather avoid the question of whether they are “constants”
as would be understood by newcomers experienced with that term in other
languages.

-- 
 \       “Crime is contagious… if the government becomes a lawbreaker, |
  `\          it breeds contempt for the law.” —Justice Louis Brandeis |
_o__)                                                                  |
Ben Finney

Thread

variable scope of class objects JonRob - 2015-10-19 14:39 -0400
  Re: variable scope of class objects Random832 <random832@fastmail.com> - 2015-10-19 15:01 -0400
    Re: variable scope of class objects JonRob - 2015-10-20 17:11 -0400
  Re: variable scope of class objects sohcahtoa82@gmail.com - 2015-10-19 16:19 -0700
    Re: variable scope of class objects Terry Reedy <tjreedy@udel.edu> - 2015-10-19 20:03 -0400
  Re: variable scope of class objects Nagy László Zsolt <gandalf@shopzeus.com> - 2015-10-20 07:31 +0200
  Re: variable scope of class objects Luca Menegotto <otlucaDELETE@DELETEyahoo.it> - 2015-10-20 08:17 +0200
    Re: variable scope of class objects Nagy László Zsolt <gandalf@shopzeus.com> - 2015-10-20 08:38 +0200
      Re: variable scope of class objects Luca Menegotto <otlucaDELETE@DELETEyahoo.it> - 2015-10-20 09:23 +0200
    Re: variable scope of class objects JonRob - 2015-10-20 17:33 -0400
      Re: variable scope of class objects Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-10-20 20:18 -0400
        Re: variable scope of class objects JonRob - 2015-10-21 19:35 -0400
          Re: variable scope of class objects Luca Menegotto <otlucaDELETE@DELETEyahoo.it> - 2015-10-22 11:59 +0200
      What does it mean for Python to have “constants”? (was: variable scope of class objects) Ben Finney <ben+python@benfinney.id.au> - 2015-10-21 11:27 +1100
      Re: What does it mean for Python to have “constants”? Nagy László Zsolt <gandalf@shopzeus.com> - 2015-10-21 08:13 +0200
      Re: variable scope of class objects Luca Menegotto <otlucaDELETE@DELETEyahoo.it> - 2015-10-22 07:55 +0200
      Re: variable scope of class objects Erik <python@lucidity.plus.com> - 2015-10-20 23:17 +0100

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