problem with 'global'

[Mel]

Duncan Booth wrote:
> Mel <mwilson at the-wire.com> wrote:
> 
>> oyster wrote:
>>> why the following 2 prg give different results? a.py is ok, but b.py
>>> is 'undefiend a'
>>> I am using Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC
>>> v.1310 32 bit (Intel)] on win32
>>> #a.py
>>> def run():
>>>         if 1==2:                # note, it always False
>>>         global a
>>>         a=1
>>>
>>> run()
>>> a
>>>
>>> #b.py
>>> def run():
>>>         a=1
>>>
>>> run()
>>> a
>> The docs seem to be in <http://www.python.org/doc/2.4/ref/global.html> 
>> but don't look all that helpful.
> 
> Why are you reading Python 2.4 docs? Try 
> http://docs.python.org/ref/global.html
> 
> The first sentence (which hasn't changed since 2.4) describing the global 
> statement seems clear enough to me: "The global statement is a declaration 
> which holds for the entire current code block."

I don't think that would stop the OP from thinking the global 
statement had to be executed.  In the code example, it seems to have 
been stuck in a

     if 1==2: global a

and it still worked.



	Mel.