[Tutor] Problems with references

[Danny Yoo]

On Tue, 1 Jun 2004, Martin Hjort Eriksen wrote:

> This is a question on how references work with Python.
>
> I have several objects, which use the same class definition. Within this
> class definition, there is an attribute of the type dictionary. During
> the run of the application, this dictionary, will be slowly filled up
> with references to other objects.


Hi Martin,


Let's look at two possible implementations of a class with an attribute:

###
class FirstExample:
    names = []
    def __init__(self):
        pass
    def add(self, name):
        self.names.append(name)
    def report(self):
        for n in names:
            print n


class SecondExample:
    def __init__(self):
        self.names = []
    def add(self, name):
        self.names.append(name)
    def report(self):
        for n in names:
            print n
###

Does your class definition resemble either one of these?

The difference between the two here is that the FirstExample uses a shared
"names"  class attribute.  The SecondExample uses an instance-specific
"names"  attribute that's created anew for each instance.


My guess is that the FirstExample's approach fits your problem
description, but then, I guess wildly.  *grin*

Please tell us a few more details on your class.  A small, simplified
example of the problem with source code will help us a lot, since then we
can duplicate the same problem.

Good luck to you!