Help, how to override <= operator

Frank Niessink frankn=news at cs.vu.nl
Thu Jun 3 09:34:53 CEST 1999


Greg Ewing <greg.ewing at compaq.com> wrote:
> Frank Niessink wrote:
>> 
>> Clemens Hintze <cle at gmx.net> wrote:
>> 
>> > class myint:
>> >     i = 0
>> 
>> This is a bit confusing because you don't need (and don't even use,
>> and probably don't _want_ to use) the class variable i.

> I beg to differ - I think that "declaring" instance variables
> in this way serves a useful documentation purpose, and I do
> so frequently.

But what is `declared' in the snippet above is a _class variable_!
If you are developing an integer class you probably don't want a 
class variable...

This is the original posters' code:
> class myint:
>     i = 0
>     def __init__(self, n):
>         self.i = n
>     def __cmp__(self, b):
>         if self.i < b.i: return -1
>         if self.i > b.i: return 1
>         return 0

The class variable i and the instance variable i are different. Example:
>>> a = myint(1)
>>> a.i
1

Because the instance variable i hides the class variable i we to access 
the class variable indirectly:
>>> a.__class__.i    
0

So my comment still stands: you don't need, don't use, and probably don't
want to use the class variable i (in this particular example of course). 

Ciao, Frank

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