On Sun, Nov 16, 2008 at 8:16 AM, Mr. SpOOn <[EMAIL PROTECTED]> wrote: > Hi, > I'm trying to create a class which inherit a list to change some behavior. > This list should contain other instance objects and has to manage > these instances in a particular way. > > 1) I need to sort this elements in this list, but they must be sorted > using an instance variable. What does Python use to sort elements? I > mean, there is a __sort__ method in the class list or it just uses > comparison operators? In this case, shall I just redefine this > operators in the element classes?
It uses the comparison operators. IIRC, at a minimum it needs __lt__ and __eq__ to be defined on the elements. > > 2) I need to have just unique elements. Maybe this is related to first > question (or maybe not). Again, to estabilish the uniqueness of an > element I have to use an instance variable. I think I have to rewrite > both the methods append() and __contains__(), but I'm not sure how. > > For the first one I did: > > def append(self, element): > if element in self: > pass > else: > list.append(self, element) You should probably use the `bisect` module (http://docs.python.org/library/bisect.html) for searching and inserting into the list as it takes advantage of and ensures that the list keeps sorted. It also means that __contains__ and some other operations become O(log N) rather than O(N). Cheers, Chris -- Follow the path of the Iguana... http://rebertia.com > > It seems right to me, but I have no idea what to do with __contains__() > > Suggestion? > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
