How to access a containing objects properties from an object inside.

nuwandame nuwandame at
Thu Mar 5 17:33:22 CET 2009

Aaron Brady wrote:
> On Mar 5, 9:51 am, nuwandame <nuwand... at> wrote:
>> Aaron Brady wrote:
>>> On Mar 5, 8:44 am, nuwandame <nuwand... at> wrote:
>>>> I have two objects obj1 and obj2. Inside obj1 there is an attribute for
>>>> success (obj1.success) and for containing other objects (
>>>> I am using setattr() to add obj2 as an attribute to
>>>> ( this is working fine.
>>>> My problem is when someone changes a variable in obj2 instance after it
>>>> is added to obj1 e.g.
>>>> = False
>>>> I am trying to figure out how to locate and access obj1.success when
>>>> obj2.success has changed.
>>>> Any assistance, pointers, ideas are much appreciated.
>>>> JJ
>>> Hi.  There's no way in general, but if you will make a few
>>> assumptions, there are some possibilities.  For example, you could
>>> make 'obj1.success' a descriptor, which searches its '__dict__', and
>>> looks for 'success' attributes in its contents.
>>> How does that strike you?
>> You suggest an interesting idea which triggered another idea...
>> Are there mechanisms for using, accessing, executing the object id?
>> objid = id(obj1)
>> If so, I could set that as an attribute in the subsequent object when
>> adding it as an attribute and then call it when values of that attribute
>> changed.
> I think what you are after is a weak value dictionary.  But why not
> just store the parent as an attribute?  obj2.parent= obj1.

Very cool!

Thanks a bunch.


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