On Aug 19, 12:16 am, Chris Rebert <c...@rebertia.com> wrote: > On Tue, Aug 18, 2009 at 3:47 PM, David<davidsh...@googlemail.com> wrote: > > Hi all, > > > I'm trying to understand how scopes work within a class definition. > > I'll quickly illustrate with an example. Say I had the following class > > definition: > > > class Abc: > > message = 'Hello World' > > > def print_message(self): > > print message > > >>>> instance = Abc() > >>>> instance.print_message() > > NameError: global name 'message' not defined > > > My question is, why? message is not defined in print_message, but it > > is defined in the enclosing scope (the class)? > > A class' scope is never consulted when resolving variable names in its > methods. > > The scopes consulted are roughly (and in this order): > 1. Local variable scope (i.e. of the current function/method) > 2. Enclosing functions (if you have functions nested inside other functions) > 3. Globals (i.e. module-level variables) > 3. Builtins (i.e. the built-in functions and methods, such as len()) > > To access class-level variables from within instance methods of the > class, you have 2 options: > A. Use the class name, i.e. Abc.message > B. Reference the class indirectly, i.e. self.__class__.message > > Cheers, > Chris > --http://blog.rebertia.com
Ah, thanks! -- http://mail.python.org/mailman/listinfo/python-list
