class - Python changing ClassA instance variables in ClassB -

i trying load whole class instance via dill rather dump , load each class variable 1 @ time.

can show me how this:

class object(object):     pass  class classa:     def __init__(self):         self.data = "initial"  class classb:     def __init__(self, ca):         self.ca = ca      def updatevalue(self):         #a = dill.load(classa.storage)         = object()         a.data = "new value"         self.ca =         print self.ca.data  ca = classa() cb = classb(ca) cb.updatevalue() print ca.data 

so output is:

new value new value 

i think you're asking:

given object , object b, how can copy of a's attributes b in 1 step (or programatically)?

naive approach:

b.__dict__ = dict(a.__dict__) # make copy objects don't share same dict 

the problem approach clobbers preexisting attributes in b did not exist in a. eg.

b.attr = "some value" b.__dict__ = dict(a.__dict__) print(hasattr(b, "attr")) # expect false 

a better approach. approach copies on a's attributes , leaves attributes exist on b, not on a, alone.

b.__dict__.update(a.__dict__) 

however, there still problems if there attributes on a's class , parent classes want copy over. think that's different question.