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Re: Why do directly imported variables behave differently than those attached to imported module?

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Dun Peal wrote:

> Hi!
> 
> Here's the demonstrating code:
> 
>     # module foo.py
>     var = 0
> 
>     def set():
>         global var
>         var = 1
> 
> Script using this module:
> 
>     import foo
>     from foo import *
> 
>     print var, foo.var
>     set()
>     print var, foo.var
> 
> Script output:
> 
>     0 0
>     0 1
> 
> Apparently, the `var` we imported from `foo` never got set, but
> `foo.var` on the imported `foo` - did. Why?

They're different because -- they're different.  `foo.var` is defined in the 
namespace of the foo module.  Introspectively, you would access it as 
`foo.__dict__['var']` .

Plain `var` is in your script's namespace so you could access it as 
`globals()['var']` .  The values given to the vars are immutable integers, 
so assignment works by rebinding.  The two different bindings in 
foo.__dict__ and globals() get bound to different integer objects.

Note too the possible use of `globals()['foo'].__dict__['var'] .  (Hope 
there are no typos in this post.)

	Mel.

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Thread

Why do directly imported variables behave differently than those attached to imported module? Dun Peal <dunpealer@gmail.com> - 2011-05-03 09:31 -0700
  Re: Why do directly imported variables behave differently than those attached to imported module? Chris Rebert <clp2@rebertia.com> - 2011-05-03 09:57 -0700
  Re: Why do directly imported variables behave differently than those attached to imported module? Daniel Kluev <dan.kluev@gmail.com> - 2011-05-04 03:57 +1100
  Re: Why do directly imported variables behave differently than those attached to imported module? Mel <mwilson@the-wire.com> - 2011-05-03 13:00 -0400
  Re: Why do directly imported variables behave differently than those attached to imported module? Terry Reedy <tjreedy@udel.edu> - 2011-05-03 13:13 -0400
  Re: Why do directly imported variables behave differently than those attached to imported module? harrismh777 <harrismh777@charter.net> - 2011-05-03 12:24 -0500
    Re: Why do directly imported variables behave differently than those attached to imported module? Dun Peal <dunpealer@gmail.com> - 2011-05-03 11:51 -0700
      Re: Why do directly imported variables behave differently than those attached to imported module? Dun Peal <dunpealer@gmail.com> - 2011-05-03 12:23 -0700
        Re: Why do directly imported variables behave differently than those attached to imported module? Daniel Kluev <dan.kluev@gmail.com> - 2011-05-04 06:55 +1100
  Re: Why do directly imported variables behave differently than those attached to imported module? Chris Angelico <rosuav@gmail.com> - 2011-05-04 07:47 +1000
    Re: Why do directly imported variables behave differently than those attached to imported module? Duncan Booth <duncan.booth@invalid.invalid> - 2011-05-04 08:44 +0000
  Re: Why do directly imported variables behave differently than those attached to imported module? Chris Rebert <clp2@rebertia.com> - 2011-05-03 15:11 -0700

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