Op 2005-01-13, harold fellermann schreef <[EMAIL PROTECTED]>: > Hi Tim, > > If you have > > class Foo(object) : > x = 0 > y = 1 > > foo = Foo() > > foo.x # reads either instance or class attribute (class in this case) > > foo.x = val # sets an instance attribute (because foo is instance not > class) > > Foo.x = val # sets a class attribute > foo.__class.__x = val # does the same > > this might be sometimes confusing. IMHO, the following is especially > nasty: > > >>> foo = Foo() > >>> foo.x += 1 > >>> > >>> print foo.x > 1 > >>> print Foo.x > 0 > > although the += operator looks like an inplace add it isn't. > it is just syntactic sugar for foo.x = foo.x + 1.
Except is x belongs to a mutable class that implements the += operator as an inplace add. Try the same but with x = [2] and foo.x += [3] -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
