Newbie question about dictionaries in classes

[Sean 'Shaleh' Perry]

On 23-Apr-2001 Jacek Pliszka wrote:
> Hi!
> 
> I just started to learn Python and I got stuck with the following
> problem:
> 
> class myclass:
>     aaa={}
>     def add(self,u):
>         (self.aaa)[u]=1
>     def show(self):
>         print self.aaa
> 
> 
> then I get the result that aaa in both ula and ola
> is identical!!! I thought that aaa will be different for
> ula and ola!!
> 
> What am I doing wrong?
> 

by placing the dictionary outside of a function in your class you made it
global to all instances of the class.  What you really want is:

def __init__(self):
    self.aaa = {}

which will give each instance its own dictionary.

The global class variables are useful for things like constants or shared data
that all instances would need.