dict: retrieve the original key by key

[Chris Rebert]

On Sun, May 15, 2011 at 1:28 AM, Christoph Groth <cwg at falma.de> wrote:
> Dear python experts,
>
> I use a huge python dictionary where the values are lists of that
> dictionary's keys (yes, a graph).  Each key is thus referenced several
> times.
>
> As the keys are rather large objects, I would like to save memory by
> re-using key objects wherever possible, instead of having several equal
> objects in memory.
>
> There does not seem to be a way to retrieve the original key from a
> python dictionary.  Is there a technical reason for this?  (Other than
> that such functionality was not considered to be useful enough.)

Define "original key".

Cheers,
Chris