Initializing a subclass with a super object?

[frankdmartinez]

Class A inherits from class B. Can anyone point me in the direction
of documentation saying how to initialize an object of A, a1, with an
object of B, b1?

[Terry]

On May 11, 7:22 am, [e-mail] wrote:

Class A inherits from class B. Can anyone point me in the direction
of documentation saying how to initialize an object of A, a1, with an
object of B, b1?

This is called a 'factory'in design patterns. Search 'python factory',
you will get a lot of examples.

br, Terry

[frankdmartinez]

Hi, Terry.
Yeah, no. If we think of the inherited B as an object nested
within a1, I'm attempting to initialize that B with b1 by accessing
the B, say, via a function call. I don't see how using a python
factory achieves this.

[Francesco Bochicchio]

On Sat, 10 May 2008 18:09:02 -0700, frankdmartinez wrote:

Hi, Terry.
Yeah, no. If we think of the inherited B as an object nested
within a1, I'm attempting to initialize that B with b1 by accessing
the B, say, via a function call. I don't see how using a python
factory achieves this.

But there is not such a thing, in Python. What you have is that A
has the same attributes/methods of B plus its own.
What you could do is adding in class A a method like this:

class A(B):
...
def set_b_attributes(self, instance_of_b):
for k, value in instance_of_b.__dict__:
setattr(self, k, value )

and the use it like this:

a1.set_b_attributes(b1)

Of course, if b attributes are few and always the same it is more
readable assigning them explicitely:

def set_b_attributes(self, instance_of_b):
self.attr1 = instance_of_b.attr1
self.attr2 = instance_of_b.attr2
....

Ciao
-----
FB

[frankdmartinez]

On May 11, 3:19*am, Francesco Bochicchio <[e-mail]:

But there is not such a thing, in Python. What you have is that A
has the same attributes/methods of B plus its own.
What you could do is *adding in class A a method like this:

* class A(B):
* * *...
* * *def set_b_attributes(self, instance_of_b):
* * * * *for k, value in instance_of_b.__dict__:
* * * * * * * * setattr(self, k, value )

and the use it like this:

* *a1.set_b_attributes(b1)

Hi, Francesco.
Thanx! That's actually exactly what I needed (though I didn't
know it).