[Python-Dev] Proposal: defaultdict

[Georg Brandl]

Guido van Rossum wrote:

>   d = DefaultDict([])
> 
> can be written as simply
> 
>   d[key].append(value)

> Feedback?

Probably a good idea, has been proposed multiple times on clpy.
One good thing would be to be able to specify either a default value
or a factory function.

While at it, other interesting dict subclasses could be:
* sorteddict, practically reinvented by every larger project
* keytransformdict, such as d = keytransformdict(str.lower).

Georg