Write this accumuator in a functional style

[Steven D'Aprano]

On Wed, 12 Jul 2017 17:47:50 +1200, Gregory Ewing wrote:

> Steve D'Aprano wrote:
>> - Greg's dict comprehension version requires N+1 passes through the
>> data,
>>   one to convert to a list, and 1 per each possible key.
> 
> Just to be clear, my solution was a response to the requirement that it
> be written in a purely functional style. It's not now I would actually
> recommend doing it!

I never imagined anything else!

-- 
Steve