Antoon Pardon wrote: > Op 2005-11-03, Steven D'Aprano schreef <[EMAIL PROTECTED]>: > > >>>There are two possible fixes, either by prohibiting instance variables >>>with the same name as class variables, which would allow any reference >>>to an instance of the class assign/read the value of the variable. Or >>>to only allow class variables to be accessed via the class name itself. >> >>There is also a third fix: understand Python's OO model, especially >>inheritance, so that normal behaviour no longer surprises you. > > > No matter wat the OO model is, I don't think the following code > exhibits sane behaviour: > > class A: > a = 1 > > b = A() > b.a += 2 > print b.a > print A.a > > Which results in > > 3 > 1
On the other hand: >>> class C: ... a = [1] ... >>> b=C() >>> b.a += [2] >>> b.a [1, 2] >>> C.a [1, 2] I can understand that Guido was a bit reluctant to introduce += etc into Python, and it's important to understand that they typically behave differently for immutable and mutable objects. -- http://mail.python.org/mailman/listinfo/python-list
