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

Aaron Brady castironpi at gmail.com
Thu Mar 5 17:00:37 CET 2009


On Mar 5, 9:51 am, nuwandame <nuwand... at hotmail.com> wrote:
> Aaron Brady wrote:
> > On Mar 5, 8:44 am, nuwandame <nuwand... at hotmail.com> wrote:
> >> I have two objects obj1 and obj2. Inside obj1 there is an attribute for
> >> success (obj1.success) and for containing other objects (obj1.data)
>
> >> I am using setattr() to add obj2 as an attribute to obj1.data
> >> (obj1.data.obj2) this is working fine.
>
> >> My problem is when someone changes a variable in obj2 instance after it
> >> is added to obj1 e.g.
>
> >> obj1.data.obj2.success = 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.



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