Global module variables as default parameters

Christoph Haas email at christoph-haas.de
Fri Sep 22 17:10:28 CEST 2006


Hi, list...

I wondered if it's possible to use global (module) variables as default 
parameters. A simple working example:

----------------------------------------
#!/usr/bin/python

globalvar = 123

def test(foo=globalvar):
  print foo

test()
----------------------------------------

Running this script prints "123". That's what I expected.

Now I'm trying the same thing in a module context. A non-working example:

test.py
----------------------------------------
#!/usr/bin/python

import TestModule

TestModule.globalvar = 123
TestModule.def1()
TestModule.def2()
----------------------------------------

TestModule.py
----------------------------------------
globalvar = 0

def def1():
  print globalvar

def def2(foo=globalvar):
  print foo
----------------------------------------

Running the test.py script prints "123" and "0". So accessing the globalvar 
in def1() works. But if I try to use the global variable as a default 
parameter in def2() it uses the default "0". What is the difference 
between these two? Are there contexts of default parameters?

Thanks for any enlightenment.

 Christoph



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