On 24/01/2015 23:41, Gary Herron wrote:
On 01/24/2015 03:22 PM, Chris Angelico wrote:
On Sun, Jan 25, 2015 at 9:57 AM, Brian Gladman <no...@nowhere.net> wrote:
But I am not clear on how to delegate from my new class to the existing
Fraction class. This is what I have:
--------------------------
class RF(Fraction):
def __new__(self, x, y):
super().__new__(self, x, y)
def is_integer(self):
return self.numerator % self.denominator == 0
def __getattr__(self, attr):
return getattr(self, attr)
If you just drop everything but your new method, it should work just
fine.
class RF(Fraction):
def is_integer(self):
return self.numerator % self.denominator == 0
However, this doesn't ensure that operations on RFs will return more
RFs - they'll often return Fractions instead. There's no easy fix for
that, sorry.
ChrisA
You can always "monkey-path" the Fraction class on the fly to add a new
method to it. I think most would consider this a bad idea, but it does
work.
Try this:
>>> from fractions import Fraction
>>> def is_integer(self):
... return self.numerator % self.denominator == 0
...
>>> Fraction.is_integer = is_integer # Monkey-patch Fraction
>>>
>>> Fraction(1,2).is_integer()
False
>>> Fraction(2,1).is_integer()
True
Gary Herron
As regards this being a bad idea I'd suggest the latest score is
Practicality 1 Purity 0 :)
--
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what you can do for our language.
Mark Lawrence
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