[Python-ideas] statistics module in Python3.4

[Wolfgang Maier]

> -----Ursprüngliche Nachricht-----
> Von: Paul Moore [mailto:p.f.moore at gmail.com]
> Gesendet: Sonntag, 2. Februar 2014 00:14
> An: Wolfgang Maier
> Cc: Python-Ideas
> Betreff: Re: [Python-ideas] statistics module in Python3.4
> 
> On 1 February 2014 22:00, Wolfgang Maier <wolfgang.maier at biologie.uni-
> freiburg.de> wrote:
> > It may also help to address this from the users' perspective. What
> > possible other use-cases could there be to pass a Mapping (let alone a
> > Counter) to one of the functions in statistics?
> 
> Why not just pass counter.elements() to the functions if you want to use a
> counter as a frequency table?
> 

The difference is that by accepting a Counter directly functions like 
statistics._sum and mode can do their job faster and more space-
efficient. Using counter.elements means exploding the data structure, 
then summing up (for _sum) all the values, while you could just sum
all key*value of the Counter.

 
> Maybe you're arguing that Mappings should be rejected with an exception?
> But that seems like an unnecessary restriction just to catch the mistaken
> usage of forgetting to call elements() on a Counter.
> 

I don't know if they should be rejected, an explicit warning in the docs that 
their treatment may be subject to change in Python3.5 may also be an 
option.

Best,
Wolfgang