Ühel kenal päeval, T, 2009-07-07 kell 13:28, kirjutas Christophe:
> Aaron S. Meurer a écrit :
> >
> > Interval(3, 4, endpoints='oc'), which would create (3, 4] ('oc' stands
> > for open-closed).
How about using '[' for closed and ']' instead of 'o' and 'c'? I find
'[]' or '][' a bit more intuitive, as it took a bit time to figure out
that 'oo' means open-open interval, not infinity..
So: cc = '[]', oc = ']]', oo = '][' and co = '[['.
> Hello here is a first try fopr working with sets. This code has been
> writing directly as I was thinking of what I neede. I think that it
> could be better. I'll work on unions of intervals : ythis would be
> simply a list of single intervals with additional methods so as to
> simplify a union. For the moment, only the intersection has been made. I
> hope that I didn't forget something.
>
> Every kind of suggestion is welcome.
Some of the comments below are influenced by "PEP 8 -- Style Guide for
Python Code" - http://www.python.org/dev/peps/pep-0008/ :)
> #!/usr/bin/env python
> #coding=utf-8
>
>
> # Code writing by BAL Christophe
> # Mail : [email protected]
>
> class Interval():
> def __init__(self, a, b, endpoints ='cc'):
> if endpoints not in ['cc', 'oc', 'co', 'oo']:
> raise Exception, 'Unkown endpoints of interval : "' +
> str(endpoints) + '"'
please use raise Exception (...)
...and note the grammar and typo.
>
> self.endpoints = endpoints
>
> if a>b:
Please use proper spacing here: a > b...
> self.min,self.max = b,a
...and here...
> self.endpoints_min, self.endpoints_max = endpoints[1],
> endpoints[0]
> else:
> self.min = a
> self.max = b
> self.endpoints_min = endpoints[0]
> self.endpoints_max = endpoints[1]
self.endpoints handling looks broken - they are not reversed here ^^
>
> def __str__(self):
> if self.min == self.max:
> if self.endpoints == 'cc':
> return '{' + str(self.min) + '}'
Should we use [ or { ??
> else:
> return 'Empty Set'
>
> if self.endpoints_min=='c':
..spacing..
> t = '['
> else:
> t =']'
>
> t+=str(self.min) + ';' + str(self.max)
...
> if self.endpoints_max=='c':
spacing
> t += ']'
> else:
> t +='['
>
> return t
>
> def intersection(self, otherInterval):
Please add docstring...
> # The intersection is empty.
> if self.min == self.max or otherInterval.min == otherInterval.max:
> return Interval(0, 0, 'oo')
>
> maxOfMins = max(self.min, otherInterval.min)
> minOfMaxs = min(self.max, otherInterval.max)
>
> if maxOfMins > minOfMaxs:
> return Interval(0, 0, 'oo')
>
> if self.min == self.max or otherInterval.min == otherInterval.max:
> return Interval(0, 0, 'oo')
>
> # The intersection could be a set with a single element.
> if minOfMaxs == maxOfMins:
> if self.max == minOfMaxs:
> if self.endpoints_max == 'o' or otherInterval.endpoints_min
> =='o':
> return Interval(0, 0, 'oo')
> else:
> return Interval(minOfMaxs, minOfMaxs)
>
> else:
> if self.endpoints_min == 'o' or otherInterval.endpoints_max
> =='o':
> return Interval(0, 0, 'oo')
> else:
> return Interval(minOfMaxs, minOfMaxs)
>
> # Wath is the endpoints of the intersection ?
> answerendpoints_min = 'c'
>
> if self.min == maxOfMins :
spacing...
> answerendpoints_min = self.endpoints_min
>
> if otherInterval.min == maxOfMins and answerendpoints_min == 'c':
> answerendpoints_min = otherInterval.endpoints_min
>
> answerendpoints_max = 'c'
>
> if self.max == minOfMaxs :
spacing..
> answerendpoints_max = self.endpoints_max
>
> if otherInterval.max == minOfMaxs and answerendpoints_max == 'c':
> answerendpoints_max = otherInterval.endpoints_max
>
> return Interval(maxOfMins, minOfMaxs,
> answerendpoints_min+answerendpoints_max)
spacing...
Also, I would prefer to have lower-case variables:
minOfMaxs vs min_of_max
Cheers,
Priit :)
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