[Python-Dev] nodef

Raymond Hettinger python at rcn.com
Thu May 24 06:47:46 CEST 2007

From: "Greg Ewing" 
> If the aforementioned iterable can yield *anything*,
> then it might yield this 'nodef' value as well.
> For this reason, there *can't* exist any *standard*
> guaranteed-unambiguous sentinel value. Each use
> case needs its own, to ensure it's truly unambiguous
> in the context of that use case.


That's why Barry and others write:

missing = object()
v = d.get(k, missing)

That is the guaranteed way to get a unique object.


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