On Jul 5, 2009, at 10:23 PM, smichr wrote:
>
>
>
> On Jul 4, 7:50 pm, Christophe <projet...@gmail.com> wrote:
>>> Python has a builtin set data type. For example:
>>
>>>>>> x= [1,2,3,5,2,1]
>>>>>> set(x)
>>
>>> set(1, 2, 3, 5)
>>
>>> Sympy has an Interval class, but it seems at the moment it doesn't
>>> have things like the intersection / union operators, nor whether the
>>> interval is open or closed.
>>
>>> I'm not sure if this Interval class was intended for the application
>>> you mentioned, but if so, we should add some functionality, it
>>> wouldn't be very hard. The file is:
>>> sympy/core/interval.py
>>
>
> The interface would have to be changed to take a descriptor of whether
> the set is open or closed, wouldn't it? But maybe you could make the
> start and end values be a tuple and change the corresponding start and
> end property definitions. So you could create an interval (3,4] like
>
> Interval((3,0),(4,1))
>
I think a default argument would be better, like
Interval(3, 4, endpoints='oc'), which would create (3, 4] ('oc' stands
for open-closed).
> And the default could be a closed set (i.e. Interval(3,4) would be
> [3,4])
I agree, make 'cc' the default.
Aaron Meurer
>
> There is a package available that already handles intervals as has
> been requested that is available at
>
> http://members.cox.net/apoco/interval/
>
> I found this on the listing of packages at http://pypi.python.org/
> pypi/
> .
>
> /c
> >
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