How to copy instances of a custom defined class in Python 3.3? -

i trying copy instances of custom class in python 3.3, similar how dict.copy() , list.copy() work. how go this?

here example of custom class:

class customclass(object): # custom class example     def __init__(self, thing):         self.thing = thing 

in general, can use copy module produce copies of python objects.

• copy.copy() produce shallow copy; new instance created attributes copied over. if of attributes mutable , mutate objects you'll see changes reflected on both objects.

• copy.deepcopy() produce copy recursively; mutable objects cloned.

if class implements __copy__ method it'll used create shallow copy of object; return new instance attributes copied on , altered needed.

similarly, can implement __deepcopy__ method implement custom deep copy method; it'll passed memo state, pass on recursive copy.deepcopy() calls.

note cannot use copy class object however. classes meant singletons; don't need create copy in case. can use subclassing instead, or class factory function, produce distinct class objects.