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Re: Dynamic variable creation from string

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On Thu, Dec 8, 2011 at 11:03 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
>> It is really important that the scope of a,b,c is limited to the Sum
>> function, they must not exisit outside it or inside any other nested
>> functions.
>
> The second part is impossible, because that is not how Python works.
> Nested functions in Python can always see variables in their enclosing
> scope. If you don't want that behaviour, use another language, or don't
> use nested functions.

To the OP: By "nested functions", did you mean actual nested functions
(those defined inside this function), or simply functions called from
this one?

This is a nested function, as the term is usually taken to mean:

def outer_function():
    a = 1
    def inner_function():
        b = 2
        return a+b
    print(inner_function())  # Prints 3

The inner function has access to all of the outer function's
namespace. But if you meant this:

def function_1():
    b = 2
    return a+b

def function_2():
    a = 1
    print(function_1())

then it's quite the other way around - Python never shares variables
in this way (this would have function_1 assume that 'a' is a global
name, so if it's not, you'll get a run-time NameError).

As Steven says, there's no way in Python to hide variables from an
actual nested function. But if you just mean a function called from
this one, then what you want is the normal behaviour (and if you
actually want to share variables, you pass them as arguments).

ChrisA

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Thread

Dynamic variable creation from string Massi <massi_srb@msn.com> - 2011-12-07 09:09 -0800
  Re: Dynamic variable creation from string John Gordon <gordon@panix.com> - 2011-12-07 17:45 +0000
    Re: Dynamic variable creation from string MRAB <python@mrabarnett.plus.com> - 2011-12-07 18:07 +0000
  Re: Dynamic variable creation from string "Waldek M." <wm@localhost.localdomain> - 2011-12-07 18:46 +0100
  Re: Dynamic variable creation from string Chris Angelico <rosuav@gmail.com> - 2011-12-08 04:52 +1100
  Re: Dynamic variable creation from string Terry Reedy <tjreedy@udel.edu> - 2011-12-07 17:59 -0500
  Re: Dynamic variable creation from string Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-08 00:03 +0000
    Re: Dynamic variable creation from string Terry Reedy <tjreedy@udel.edu> - 2011-12-07 19:27 -0500
      Re: Dynamic variable creation from string Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-08 01:59 +0000
      Re: Dynamic variable creation from string Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-12-08 10:54 +0200
        Re: Dynamic variable creation from string Massi <massi_srb@msn.com> - 2011-12-09 01:55 -0800
          Re: Dynamic variable creation from string Peter Otten <__peter__@web.de> - 2011-12-09 12:27 +0100
          Re: Dynamic variable creation from string Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-09 11:59 +0000
            Re: Dynamic variable creation from string Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-09 12:03 +0000
            Re: Dynamic variable creation from string Chris Angelico <rosuav@gmail.com> - 2011-12-09 23:08 +1100
          Re: Dynamic variable creation from string Ethan Furman <ethan@stoneleaf.us> - 2011-12-09 12:01 -0800
          Re: Dynamic variable creation from string Nobody <nobody@nowhere.com> - 2011-12-11 06:42 +0000
            Re: Dynamic variable creation from string alex23 <wuwei23@gmail.com> - 2011-12-11 19:31 -0800
              Re: Dynamic variable creation from string Ethan Furman <ethan@stoneleaf.us> - 2011-12-11 21:00 -0800
                Re: Dynamic variable creation from string alex23 <wuwei23@gmail.com> - 2011-12-11 22:50 -0800
    Re: Dynamic variable creation from string Chris Angelico <rosuav@gmail.com> - 2011-12-08 14:13 +1100
  Re: Dynamic variable creation from string alex23 <wuwei23@gmail.com> - 2011-12-11 23:11 -0800
    Re: Dynamic variable creation from string 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-12 04:43 -0800
    Re: Dynamic variable creation from string 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-12 04:49 -0800
      Re: Dynamic variable creation from string alex23 <wuwei23@gmail.com> - 2011-12-12 15:45 -0800
        Re: Dynamic variable creation from string Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-13 01:35 +0000
          Re: Dynamic variable creation from string 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-13 06:21 -0800

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