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Re: Python Newbie

From "J.R." <groups_jr-1@yahoo.com.br>
Newsgroups comp.lang.python
Subject Re: Python Newbie
Date 2013-02-24 23:02 -0300
Organization Aioe.org NNTP Server
Message-ID <kgegna$koj$1@speranza.aioe.org> (permalink)
References <cad0eacc-6040-4a00-bd05-7fabfd2fa70e@googlegroups.com> <5c262e95-b3a8-4f2a-b752-84b30bf4f81e@googlegroups.com>

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On 21/02/2013 19:40, piterrr.dolinski@gmail.com wrote:

<snip>

> I am nervous about using variables "out of the blue", without having
> to declare them. For example, when I write "i = 0" it is perfectly OK
> to Python without 'i' being declared earlier. How do I know that I
> haven't used this variable earlier and I am unintentionally
> overwriting the value? I find I constantly have to use the search
> facility in the editor, which is not fun.
>
> You see, Javascript, for one, behaves the same way as Python (no
> variable declaration) but JS has curly braces and you know the
> variable you have just used is limited in scope to the code within
> the { }. With Python, you have to search the whole file.
>

No, JavaScript - or better, ECMAScript -, does have variable 
declaration. If you don't declare a variable with the "var" statement it 
will become an unintentional global variable which is a very bad thing.

If the variable statement occurs inside a Function Declaration, the 
variables are defined with function-local scope in that function. 
Otherwise, they are defined with global scope (that is, they
are created as members of the global object. Variables are created when 
the execution scope is entered. A Block { } does not define a new 
execution scope.

PS.: JavaScript is a trademark, and the actual language name is 
specified as ECMAScript.

See <http://ecma-international.org/ecma-262/5.1/>

-- 
Joao Rodrigues (J.R.)

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Thread

Python Newbie Piterrr <piterrr.dolinski@gmail.com> - 2013-02-21 13:26 -0800
  Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-21 14:54 -0700
  Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-21 21:58 +0000
  Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 08:59 +1100
  Re: Python Newbie Peter Pearson <ppearson@nowhere.invalid> - 2013-02-21 22:03 +0000
  Re: Python Newbie Dave Angel <davea@davea.name> - 2013-02-21 17:22 -0500
  Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-21 14:40 -0800
    Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 10:21 +1100
      Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-21 15:34 -0800
        Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-21 23:48 +0000
        Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 11:32 +1100
        Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 11:58 -0700
      Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-21 15:34 -0800
    Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-21 23:27 +0000
    Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-21 16:55 -0700
    Re: Python Newbie rusi <rustompmody@gmail.com> - 2013-02-21 22:57 -0800
    Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-22 10:26 +0000
      Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-22 12:05 +0100
      Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 22:23 +1100
    Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 16:04 -0700
    Re: Python Newbie Vito De Tullio <vito.detullio@gmail.com> - 2013-02-24 09:23 +0100
    Re: Python Newbie "J.R." <groups_jr-1@yahoo.com.br> - 2013-02-24 23:02 -0300
      Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 21:03 -0500
        Re: Python Newbie "J.R." <groups_jr-1@yahoo.com.br> - 2013-02-24 23:35 -0300
        Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 13:31 +1100
  Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-21 19:35 -0500
  Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-21 23:50 -0500
    Re: Python Newbie Rui Maciel <rui.maciel@gmail.com> - 2013-02-22 11:58 +0000
      Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 23:12 +1100
        Re: Python Newbie Rui Maciel <rui.maciel@gmail.com> - 2013-02-22 13:50 +0000
          Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 01:05 +1100
            Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-23 00:03 +0000
              Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 11:21 +1100
          Re: Python Newbie Duncan Booth <duncan.booth@invalid.invalid> - 2013-02-22 14:26 +0000
            Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-22 15:45 +0100
              Re: Python Newbie Duncan Booth <duncan.booth@invalid.invalid> - 2013-02-22 15:02 +0000
            Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 02:06 +1100
              Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 13:37 -0800
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-22 22:08 +0000
                Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-22 15:45 -0700
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 15:38 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 11:17 +1100
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-23 13:29 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 08:38 +1100
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 15:52 -0700
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 10:18 +1100
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-23 15:46 -0800
                Re: Python Newbie Larry Hudson <orgnut@yahoo.com> - 2013-02-23 20:20 -0800
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 14:34 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 07:46 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 02:52 +1100
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 11:22 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-24 17:44 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 11:29 -0800
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 21:35 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 14:43 -0800
                Re: Python Newbie Joel Goldstick <joel.goldstick@gmail.com> - 2013-02-24 18:05 -0500
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 23:13 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 14:43 -0800
                Re: Python Newbie Larry Hudson <orgnut@yahoo.com> - 2013-02-26 00:32 -0800
                Re: Python Newbie rurpy@yahoo.com - 2013-02-26 10:23 -0800
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-26 10:59 -0800
                Re: Python Newbie rurpy@yahoo.com - 2013-02-26 13:30 -0800
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 18:31 -0700
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 09:08 +1100
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-24 23:18 +0000
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 22:51 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 15:38 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 10:45 +1100
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 15:53 -0800
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 16:08 -0800
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-25 00:28 +0000
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-25 00:38 +0000
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 16:33 -0800
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-25 00:45 +0000
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 19:50 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 01:04 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 12:27 +1100
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 18:42 -0700
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 12:24 +1100
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-25 01:44 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 12:53 +1100
                Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-25 02:23 +0000
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 18:59 -0800
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 16:08 -0800
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 19:42 -0500
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 15:38 -0800
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 23:21 +0000
                Re: Python Newbie Dave Angel <davea@davea.name> - 2013-02-24 17:47 -0500
                Re: Python Newbie Serhiy Storchaka <storchaka@gmail.com> - 2013-02-25 14:40 +0200
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 07:46 -0800
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 22:23 -0700
                Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-24 00:11 +0000
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 12:37 -0500
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 10:56 -0700
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 13:07 -0500
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 21:01 -0500
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 15:38 -0800
                Re: Python Newbie Terry Reedy <tjreedy@udel.edu> - 2013-02-22 20:04 -0500
                Re: Python Newbie rurpy@yahoo.com - 2013-02-22 18:48 -0800
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-22 20:47 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-23 02:02 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 13:18 +1100
                Re: Python Newbie Grant Edwards <invalid@invalid.invalid> - 2013-02-24 18:19 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:25 +1100
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-22 21:40 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 13:48 +1100
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-23 02:59 +0000
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-23 13:34 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 08:40 +1100
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 12:41 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-23 04:13 +0000
                Re: Python Newbie Serhiy Storchaka <storchaka@gmail.com> - 2013-02-23 11:48 +0200
                Re: Python Newbie Rui Maciel <rui.maciel@gmail.com> - 2013-02-23 12:30 +0000
                Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-23 16:43 +0100
                Re: Python Newbie jmfauth <wxjmfauth@gmail.com> - 2013-02-23 10:44 -0800
                Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-23 12:13 -0700
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-23 11:08 -0800
                Re: Python Newbie jmfauth <wxjmfauth@gmail.com> - 2013-02-23 12:53 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 08:48 +1100
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 00:02 +0000
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 12:16 -0700
                Re: Python Newbie Matej Cepl <mcepl@redhat.com> - 2013-02-24 00:06 +0100
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 02:51 +1100
                Re: Python Newbie Matej Cepl <mcepl@redhat.com> - 2013-02-24 00:04 +0100
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-23 08:32 -0800
                Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-23 18:39 +0100
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 12:19 -0700
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 17:11 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 11:40 -0800
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-24 15:06 -0500
                Re: Python Newbie "Michael Ross" <gmx@ross.cx> - 2013-02-24 21:33 +0100
                Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-24 20:34 +0000
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 20:41 +0000
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 12:34 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:42 +1100
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 15:48 -0500
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 21:58 +0000
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 21:08 -0500
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-25 02:59 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:47 +1100
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:58 +1100
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 16:08 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 08:44 +1100
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-24 17:40 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 01:11 +0000
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 00:42 +0000
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 18:34 -0700
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 14:33 -0800
                Re: Python Newbie Albert Hopkins <marduk@letterboxes.org> - 2013-02-24 18:32 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 10:44 +1100
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 01:06 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 11:40 -0800
              Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 13:37 -0800
      Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-22 20:05 -0500
  Re: Python Newbie Gene Heskett <gheskett@wdtv.com> - 2013-02-23 12:32 -0500
  Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-23 19:10 +0100
  Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 11:40 -0700
  Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 12:15 -0700
  Re: Python Newbie Gene Heskett <gheskett@wdtv.com> - 2013-02-23 17:49 -0500
  Re: Python Newbie Nick Mellor <thebalancepro@gmail.com> - 2013-02-25 19:37 -0800

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