[Python-ideas] Fwd: stats module Was: minmax() function ...

Raymond Hettinger raymond.hettinger at gmail.com
Fri Oct 15 22:01:37 CEST 2010

Drat.  This should have gone to python-ideas.

Begin forwarded message:

> From: Raymond Hettinger <raymond.hettinger at gmail.com>
> Date: October 15, 2010 1:00:16 PM PDT
> To: Python-Dev Dev <python-dev at python.org>
> Subject: Fwd: [Python-ideas] stats module Was: minmax() function ...
> Hello guys.  If you don't mind, I would like to hijack your thread :-)
> ISTM, that the minmax() idea is really just an optimization request.
> A single-pass minmax() is easily coded in simple, pure-python,
> so really the discussion is about how to remove the loop overhead
> (there isn't much you can do about the cost of the two compares
> which is where most of the time would be spent anyway).
> My suggestion is to aim higher.   There is no reason a single pass
> couldn't also return min/max/len/sum and perhaps even other summary
> statistics like sum(x**2) so that you can compute standard deviation 
> and variance.
> A few years ago, Guido and other python devvers supported a
> proposal I made to create a stats module, but I didn't have time
> to develop it.  The basic idea was that python's batteries should
> include most of the functionality available on advanced student
> calculators.  Another idea behind it was that we could invisibility
> do-the-right-thing under the hood to help users avoid numerical
> problems (i.e. math.fsum(s)/len(s) is a more accurate way to
> compute an average because it doesn't lose precision when
> building-up the intermediate sums).
> I think the creativity and energy of this group is much better directed
> at building a quality stats module (perhaps with some R-like capabilities).
> That would likely be a better use of energy than bike-shedding 
> about ways to speed-up a trivial piece of code that is ultimately
> constrained by the cost of the compares per item.
> my-two-cents,
> Raymond

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