Alexander Zatvornitskiy wrote: > Hello! > > I have trouble with copy/deepcopy. It seems, I just don't understand something. > Please explain where things goes wrong and how to do it the right way. > > I have one class: > > class Distribution: > __gr_on_transp=dict() > __ostatok_m=dict() > and so on > > And, I want to make full copy of it: > d1=Distribution() > d2=copy.deepcopy(d1) > > But, members-dictionaries are don't copied. For example if I will write: > d1.clear() > which clears all two dictionaries, I will find that d2's dictionaries are also > empty!!! > > Now I'am using the quick-hack: > > class Distribution: > __gr_on_transp=dict() > __ostatok_m=dict() > ... > def my_copy(self): > d2=copy.deepcopy(self) > d2.__gr_on_transp=self.__gr_on_transp.copy() > d2.__ostatok_m=self.__ostatok_m.copy() > return d2 > > It's work well, but I don't understand why previous is wrong and how to do it > in right way. > > Alexander, [EMAIL PROTECTED]
Hello, Alexander, I just asked about deepcopy here in comp.lang.python a few weeks ago. Here is a link to that discussion: http://groups-beta.google.com/group/comp.lang.python/browse_frm/thread/41269228e1827a87 You have the right idea when you create a special method inside your class to handle the deepcopy operation. But if you call that method __deepcopy__, then copy.deepcopy() can find it and call it. In my code, it was also important that I declare my class as a new-style class, so that I could use the __new__ method. __new__ constructs a new instance of the class without initializing it. To make your class into a new-style class, you would write "class Distribution(object):" instead of just "class Distribution:". There are more details in the discussion that I referenced above. Hope that helps! -- Rainforest laid low. "Wake up and smell the ozone," Says man with chainsaw. John J. Ladasky Jr., Ph.D. -- http://mail.python.org/mailman/listinfo/python-list
