static variables in Python?

[Larry Bates]

kj wrote:
> Yet another noob question...
> 
> Is there a way to mimic C's static variables in Python?  Or something
> like it?  The idea is to equip a given function with a set of
> constants that belong only to it, so as not to clutter the global
> namespace with variables that are not needed elsewhere.
> 
> For example, in Perl one can define a function foo like this 
> 
> *foo = do {
>   my $x = expensive_call();
>   sub {
>     return do_stuff_with( $x, @_ );
>   }
> };
> 
> In this case, foo is defined by assigning to it a closure that has
> an associated variable, $x, in its scope.
> 
> Is there an equivalent in Python?
> 
> Thanks!
> 
> kynn


First names in Python are just that, names that point to objects.  Those objects 
can contain any type of information including other objects.  They are NOT 
buckets where things are stored.

1) Names (variables in Perl/C) defined within a Python function are placed in 
its local namespace.  They are not visible in the global namespace.

2) Yes you can have a local name point to a global.  This is often used in 
classes with attributes because looking up local is somewhat quicker than 
looking up the class attribute.

def foo():
   x = expensive_call
   return do_stuff_with(x())

In this particular case it doesn't really help.

It would be more useful in something like:

class foo(object):
     def __init__(self, initialvalue = 0)
         self.currentvalue = initialvalue

     def longloopingmethod(self, listtosum):
         currentvalue = self.currentvalue
         for v in listtosum:
             currentvalue += v


BTW - There are BETTER ways to sum a list, so this is just an example.

-Larry