defaultdict and dict?

Raymond Hettinger python at
Sat Nov 10 00:29:39 CET 2007

On Nov 9, 3:01 am, Davy <zhushe... at> wrote:
> In Python 2.5 document, defaultdict is called high performance
> container. From document, we can know defaultdict is subclass of dict.
> So, why defaultdict have higher performance than dict? And at what
> circumstance, we can make use of such high performance?

Defaultdicts only area of superiority is the speed and code economy
for the case where you need to automatically fill-in missing values
(it runs circles around dict.setdefault).


More information about the Python-list mailing list