Ok, thanks. I didn't know about new-style classes (I had learned python from a book prior to them).
After reading about new-style classes, I find that your solution is better because, using super (in general) avoids cl2 from having to know the implementation details of cl1. This is clearly explained in: http://www.python.org/2.2.3/descrintro.html#cooperation Also, when using new-style classes with IDLE, I found some problems which I talk about in "Modifying CallTips.py to work with with new-style classes in IDLE.", which I posted in this group. Steven Bethard wrote: > [EMAIL PROTECTED] wrote: > > Hello I have a question about inheritance in Python. I'd like to do > > something like this: > > > > class cl1: > > def __init__(self): > > self.a = 1 > > > > class cl2(cl1): > > def __init__(self): > > self.b = 2 > > > > But in such a way that cl2 instances have atributes 'b' AND 'a'. > > Obviously, this is not the way of doing it, because the __init__ > > definition in cl2 overrides cl1's __init__. > > > > Is there a 'pythonic' way of achieving this? > > If there's a chance you might have multiple inheritance at some point in > this hierarchy, you might also try using super: > > class cl1(object): # note it's a new-style class > def __init__(self): > self.a = 1 > > class cl2(cl1): > def __init__(self): > super(cl2, self).__init__() > self.b = 2 > > Note that you probably want a new-style class even if you chose not to > use super in favor of Jp Calderone's suggestion. There are very few > cases for using old-style classes these days. > > STeVe -- http://mail.python.org/mailman/listinfo/python-list
