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Re: unorderable error: less ok, equal ok, less-or-equal gives unorderable error!

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On Monday, June 30, 2014 3:34:25 PM UTC-4, Peter Otten wrote:
> RainyDay wrote:
> 
> 
> 
> > Hi, in python 3.4.1, I get this surpising behaviour:
> 
> > 
> 
> >>>> l=Loc(0,0)
> 
> >>>> l2=Loc(1,1)
> 
> >>>> l>l2
> 
> > False
> 
> >>>> l<l2
> 
> > True
> 
> >>>> l<=l2
> 
> > Traceback (most recent call last):
> 
> >   File "<stdin>", line 1, in <module>
> 
> > TypeError: unorderable types: Loc() <= Loc()
> 
> >>>> l==l2
> 
> > False
> 
> >>>> l<l2 or l==l2
> 
> > True
> 
> > 
> 
> > Loc implements both __lt__ and __eq__, which should be enough (?),
> 
> 
> 
> These two methods should be sufficient if you use the 
> 
> functools.total_ordering class decorator, see


Thanks! I literally failed to read one more paragraph in a SO answer
which referenced this decorator. I really need to start reading those
paragraphs, they often provide answers...

> > but even after I've added __lte__, I still have the error.
> 
> 
> 
> There is no special method of that name; it should probably be __le__().


Right, I used lte in django and assumed they were consistent with python.
 
> >     def __eq__(self, other):
> 
> >         return self._loc == getattr(other, "_loc", None)
> 
> 
> 
> Note that None is not a good default when _loc is expected to be a tuple:
> 

I'm only using None in equality comparison, it's never a default value of
_loc itself, so this should be ok because it'll compare to all other object
types and correctly say they're unequal.

 
 - andrei

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unorderable error: less ok, equal ok, less-or-equal gives unorderable error! RainyDay <andrei.avk@gmail.com> - 2014-06-30 12:12 -0700
  Re: unorderable error: less ok, equal ok, less-or-equal gives unorderable error! Peter Otten <__peter__@web.de> - 2014-06-30 21:34 +0200
    Re: unorderable error: less ok, equal ok, less-or-equal gives unorderable error! RainyDay <andrei.avk@gmail.com> - 2014-06-30 13:29 -0700
  Re: unorderable error: less ok, equal ok, less-or-equal gives unorderable error! Ethan Furman <ethan@stoneleaf.us> - 2014-06-30 12:52 -0700
  Re: unorderable error: less ok, equal ok, less-or-equal gives unorderable error! Peter Otten <__peter__@web.de> - 2014-07-01 14:43 +0200

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