[Python-Dev] PEP 450 adding statistics module
R. David Murray
rdmurray at bitdance.com
Fri Aug 16 01:30:34 CEST 2013
On Thu, 15 Aug 2013 23:28:39 +0300, Michael Foord <fuzzyman at voidspace.org.uk> wrote:
>
> On 15 Aug 2013, at 21:10, "Eric V. Smith" <eric at trueblade.com> wrote:
>
> > On 08/15/2013 01:58 PM, Mark Dickinson wrote:
> >> On Thu, Aug 15, 2013 at 2:08 PM, Steven D'Aprano <steve at pearwood.info
> >> <mailto:steve at pearwood.info>> wrote:
> >>
> >>
> >> - Each scheme ended up needing to be a separate function, for ease
> >> of both implementation and testing. So I had four private median
> >> functions, which I put inside a class to act as namespace and avoid
> >> polluting the main namespace. Then I needed a "master function" to
> >> select which of the methods should be called, with all the
> >> additional testing and documentation that entailed.
> >>
> >>
> >> That's just an implementation issue, though, and sounds like a minor
> >> inconvenience to the implementor rather than anything serious; I don't
> >> think that that should dictate the API that's used.
> >>
> >> - The API doesn't really feel very Pythonic to me. For example, we
> >> write:
> >>
> >>
> >> And I guess this is subjective: conversely, the API you're proposing
> >> doesn't feel Pythonic to me. :-) I'd like the hear the opinion of other
> >> python-dev readers.
> >
> > I agree with Mark: the proposed median, median.low, etc., doesn't feel
> > right. Is there any example of doing this in the stdlib? I suggest just
> > median(), median_low(), etc.
> >
> > If we do end up keeping it, simpler than the callable singleton is:
> >
> >>>> def median(): return 'median'
> > ...
> >>>> def _median_low(): return 'median.low'
> > ...
> >>>> median.low = _median_low
> >>>> del _median_low
> >>>> median()
> > 'median'
> >>>> median.low()
> > 'median.low'
>
>
> There's the patch decorator in unittest.mock which provides:
>
> patch(...)
> patch.object(...)
> patch.dict(...)
>
> The implementation is exactly as you suggest. (e.g. patch.object = _patch_object)
Truthfully there are a number of things about the mock API that make me
uncomfortable, including that one. But despite that I'm glad we
didn't try to re-engineer it. Take that as you will :)
--David
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