[Tutor] Changing a class into a subclass

Bob Gailer bgailer at alum.rpi.edu
Thu Mar 24 20:02:29 CET 2005


At 10:30 AM 3/24/2005, Max Noel wrote:

>On Mar 24, 2005, at 18:07, Ismael Garrido wrote:
>
>>Hello.
>>
>>I have a program that saves/loads to/from XML. I have a main class 
>>Building, and a subclass House(Building). When I save the code I instruct 
>>each object to save itself to XML (using ElementTree), so House adds 
>>itself to the XML tree.
>>My problem is when I load the XML. Before having subclasses what I did 
>>was to send the XML object (again in ElementTree) to the object and let 
>>itself load. Now, with subclasses, if I send the House XML to Building I 
>>get a Building instance, when I need a House instance.
>
>         You can't make an object transform into an object of a different 
> class

Are you referring to a Python object? If so you may assign a class to the 
object's __class__ attribute.
class A:pass
class B:pass
b = b()
print b.__class__ # displays <class __main__.B at 0x011BB9C0>
b.__class__ = A
print b.__class__ # displays <class __main__.A at 0x011BBA20>

[snip]

Bob Gailer
mailto:bgailer at alum.rpi.edu
510 558 3275 home
720 938 2625 cell  
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