Sandra-24 wrote:
> Can you create an instance of a subclass using an existing instance of
> the base class?
>
> Such things would be impossible in some languages or very difficult in
> others. I wonder if this can be done in python, without copying the
> base class instance, which in my case is a very expensive object.
You can change the class of an instance by assigning to the __class__
attribute. The new class doesn't even need to be a subclass of the old:
>>> class A(object):
... def __init__(self, name):
... self.name = name
... def show(self): print self.name
...
>>> a = A("alpha")
>>> a.show()
alpha
>>> class B(object):
... def show(self): print self.name.upper()
...
>>> a.__class__ = B
>>> a.show()
ALPHA
Peter
--
http://mail.python.org/mailman/listinfo/python-list
