Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #62348

Re: Experiences/guidance on teaching Python as a first programming language

References (8 earlier) <roy-B8D4E2.19322017122013@news.panix.com> <52b0fb4f$0$29973$c3e8da3$5496439d@news.astraweb.com> <mailman.4330.1387338989.18130.python-list@python.org> <52b15a69$0$29973$c3e8da3$5496439d@news.astraweb.com> <l8t7s3$b1p$1@ger.gmane.org>
From Oscar Benjamin <oscar.j.benjamin@gmail.com>
Date 2013-12-19 00:21 +0000
Subject Re: Experiences/guidance on teaching Python as a first programming language
Newsgroups comp.lang.python
Message-ID <mailman.4390.1387412489.18130.python-list@python.org> (permalink)

Show all headers | View raw

On 18 December 2013 22:33, Terry Reedy <tjreedy@udel.edu> wrote:
> On 12/18/2013 3:18 AM, Steven D'Aprano wrote:
>
>> We don't know what locals()['spam'] = 42 will do inside a function,
>
> I am mystified that you would write this. Locals() will "Update and return a
> dictionary representing the current local symbol table." The only thing
> unspecified is the relation between the 'current local symbol table' and the
> *dict* that 'represents' it. Given that a dict is returned, the rest is
> unambiguous.

It's not unambiguous. The full wording is:
'''
locals()

Update and return a dictionary representing the current local symbol
table. Free variables are returned by locals() when it is called in
function blocks, but not in class blocks.

Note:
The contents of this dictionary should not be modified; changes may
not affect the values of local and free variables used by the
interpreter.
'''

The part that says "changes may ..." is deliberately ambiguous; the
author didn't want to impose too strong a constraint on any particular
implementation.

>> unlike the C case, we can reason about it:
>>
>> - it may bind 42 to the name "spam";
>
> "somedict['spam'] = 42" will do exactly that.

That's not what is usually meant by "name-binding".

>> - it may raise a runtime exception;
>
> Absolutely not.

Agreed.

>> - it may even be a no-op;
>
> Absolutely not.

Incorrect. The code in question is:

    locals()['spam'] = 42

and it is semantically a no-op. The index assignment on a temporary
dict may actually be performed by e.g. the CPython interpreter but it
is really just dead code.


Oscar

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Experiences/guidance on teaching Python as a first programming language Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-12-09 12:23 +0000
  Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-09 05:54 -0800
  Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-09 08:57 -0800
    Re: Experiences/guidance on teaching Python as a first programming language William Ray Wing <wrw@mac.com> - 2013-12-09 12:55 -0500
    Re: Experiences/guidance on teaching Python as a first programming language Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-10 18:25 +1300
      Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-10 16:55 +1100
        Re: Experiences/guidance on teaching Python as a first programming   language Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-11 10:38 +1300
      Re: Experiences/guidance on teaching Python as a first programming language Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-10 20:35 -0500
        Re: Experiences/guidance on teaching Python as a first programming language Denis McMahon <denismfmcmahon@gmail.com> - 2013-12-11 02:16 +0000
          Re: Experiences/guidance on teaching Python as a first programming language Larry Martell <larry.martell@gmail.com> - 2013-12-11 07:08 -0500
        Re: Experiences/guidance on teaching Python as a first programming language Grant Edwards <invalid@invalid.invalid> - 2013-12-11 15:05 +0000
        Re: Experiences/guidance on teaching Python as a first programming language Rick Johnson <rantingrickjohnson@gmail.com> - 2013-12-16 16:47 -0800
          Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-16 20:06 -0500
            Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-17 01:25 +0000
            Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-17 12:27 +1100
            Re: Experiences/guidance on teaching Python as a first programming language Gene Heskett <gheskett@wdtv.com> - 2013-12-16 20:32 -0500
            Re: Experiences/guidance on teaching Python as a first programming language "Cousin Stanley" <cousinstanley@gmail.com> - 2013-12-17 07:32 -0700
              Re: Experiences/guidance on teaching Python as a first programming language Gene Heskett <gheskett@wdtv.com> - 2013-12-17 12:27 -0500
      Re: Experiences/guidance on teaching Python as a first programming language Neil Cerutti <neilc@norwich.edu> - 2013-12-11 15:46 +0000
  Re: Experiences/guidance on teaching Python as a first programming language "Rhodri James" <rhodri@wildebst.demon.co.uk> - 2013-12-09 23:32 +0000
    Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-09 18:42 -0500
      Re: Experiences/guidance on teaching Python as a first programming language "Rhodri James" <rhodri@wildebst.demon.co.uk> - 2013-12-10 00:00 +0000
      Re: Experiences/guidance on teaching Python as a first programming language Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-09 20:56 -0500
  Re: Experiences/guidance on teaching Python as a first programming language Wolfgang Keller <feliphil@gmx.net> - 2013-12-12 21:36 +0100
    Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-13 08:12 +1100
      Re: Experiences/guidance on teaching Python as a first programming language Wolfgang Keller <feliphil@gmx.net> - 2013-12-16 21:32 +0100
        Re: Experiences/guidance on teaching Python as a first programming language "Rhodri James" <rhodri@wildebst.org.uk> - 2013-12-16 23:01 +0000
        Re: Experiences/guidance on teaching Python as a first programming language Ned Batchelder <ned@nedbatchelder.com> - 2013-12-16 19:28 -0500
          Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-16 16:39 -0800
            Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-17 11:44 +1100
              Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-16 17:58 -0800
            Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-17 02:33 +0000
              Re: Experiences/guidance on teaching Python as a first programming language Rick Johnson <rantingrickjohnson@gmail.com> - 2013-12-16 20:41 -0800
              Re: Experiences/guidance on teaching Python as a first programming language Neil Cerutti <neilc@norwich.edu> - 2013-12-17 14:51 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-17 09:54 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-17 15:07 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-17 15:24 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-17 15:35 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Larry Martell <larry.martell@gmail.com> - 2013-12-17 11:21 -0500
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-17 08:56 -0800
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-17 10:03 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 05:20 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Joel Goldstick <joel.goldstick@gmail.com> - 2013-12-17 13:39 -0500
                Re: Experiences/guidance on teaching Python as a first programming language dkcombs@panix.com (David Combs) - 2014-01-29 03:17 +0000
            Re: Experiences/guidance on teaching Python as a first programming language Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-12-17 11:12 +0000
              Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-17 12:18 +0000
              Re: Experiences/guidance on teaching Python as a first programming language Wolfgang Keller <feliphil@gmx.net> - 2013-12-17 16:51 +0100
                Re: Experiences/guidance on teaching Python as a first programming language Grant Edwards <invalid@invalid.invalid> - 2013-12-17 16:59 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Larry Martell <larry.martell@gmail.com> - 2013-12-17 12:18 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-17 17:24 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-17 17:44 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Grant Edwards <invalid@invalid.invalid> - 2013-12-17 19:38 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-17 19:39 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Grant Edwards <invalid@invalid.invalid> - 2013-12-18 18:05 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-18 18:17 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-18 20:49 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-19 02:05 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Wolfgang Keller <feliphil@gmx.net> - 2013-12-19 15:54 +0100
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-18 20:40 -0500
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-18 20:05 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-18 23:16 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-19 15:26 +1100
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-18 20:48 -0800
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-19 09:14 -0800
                Re: Experiences/guidance on teaching Python as a first programming language 88888 Dihedral <dihedral88888@gmail.com> - 2013-12-18 22:03 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-19 19:40 +1300
                Re: Experiences/guidance on teaching Python as a first programming language Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-17 20:20 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-12-17 17:09 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-17 19:32 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve@pearwood.info> - 2013-12-18 01:33 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 13:11 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve@pearwood.info> - 2013-12-18 08:22 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 19:32 +1100
                Re: Experiences/guidance on teaching Python as a first programming
 language Dave Angel <davea@davea.name> - 2013-12-18 07:53 -0500
                Re: Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-19 01:55 +1100
                Re: Re: Experiences/guidance on teaching Python as a first programming language "Rhodri James" <rhodri@wildebst.org.uk> - 2013-12-19 00:10 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Neil Cerutti <neilc@norwich.edu> - 2013-12-18 15:17 +0000
                Re: Re: Experiences/guidance on teaching Python as a first
 programming language Dave Angel <davea@davea.name> - 2013-12-18 15:52 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-19 19:41 +1300
                Re: Experiences/guidance on teaching Python as a first programming
 language Dave Angel <davea@davea.name> - 2013-12-19 07:06 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Grant Edwards <invalid@invalid.invalid> - 2013-12-18 18:00 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-18 18:07 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-18 20:56 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-19 18:39 +1300
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-19 00:56 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Paul Smith <paul@mad-scientist.net> - 2013-12-17 22:49 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve@pearwood.info> - 2013-12-18 08:18 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 19:51 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-19 16:20 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-20 04:02 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Ethan Furman <ethan@stoneleaf.us> - 2013-12-18 07:23 -0800
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-18 08:53 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-18 19:29 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-19 16:20 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-18 17:15 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-19 17:12 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-20 04:28 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Neil Cerutti <neilc@norwich.edu> - 2013-12-19 18:40 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-20 07:18 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-19 19:38 -0500
                Re: Experiences/guidance on teaching Python as a first programming language "Rhodri James" <rhodri@wildebst.org.uk> - 2013-12-20 00:45 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-20 02:16 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-20 18:58 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Ned Batchelder <ned@nedbatchelder.com> - 2013-12-20 21:04 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-27 14:35 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Terry Reedy <tjreedy@udel.edu> - 2013-12-18 17:33 -0500
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-19 17:06 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-20 04:18 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-12-19 00:21 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve@pearwood.info> - 2013-12-18 07:53 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Devin Jeanpierre <jeanpierreda@gmail.com> - 2013-12-17 18:33 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 14:01 +1100
                Re: Experiences/guidance on teaching Python as a first programming language Devin Jeanpierre <jeanpierreda@gmail.com> - 2013-12-17 19:12 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 14:24 +1100
                Re: Experiences/guidance on teaching Python as a first programming language "Rhodri James" <rhodri@wildebst.org.uk> - 2013-12-19 00:49 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-19 11:54 +1100
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-18 20:29 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-19 04:50 +0000
                Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-18 21:09 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-19 05:36 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-19 21:31 +0000
                Re: Experiences/guidance on teaching Python as a first programming language Roy Smith <roy@panix.com> - 2013-12-19 19:30 -0500
              Re: Experiences/guidance on teaching Python as a first programming language rusi <rustompmody@gmail.com> - 2013-12-18 01:18 -0800
                Re: Experiences/guidance on teaching Python as a first programming language Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-12-18 10:06 +0000
            Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-18 01:10 +1100
          Re: Experiences/guidance on teaching Python as a first programming language Wolfgang Keller <feliphil@gmx.net> - 2013-12-17 16:22 +0100
            Re: Experiences/guidance on teaching Python as a first programming language Wolfgang Keller <feliphil@gmx.net> - 2013-12-19 16:14 +0100
              Re: Experiences/guidance on teaching Python as a first programming   language Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-20 09:42 +1300
                Re: Experiences/guidance on teaching Python as a first programming language Chris Angelico <rosuav@gmail.com> - 2013-12-20 07:51 +1100
        Re: Experiences/guidance on teaching Python as a first programming language dkcombs@panix.com (David Combs) - 2014-01-29 03:09 +0000

csiph-web