sequence multiplied by -1
Emile van Sebille
emile at fenx.com
Fri Oct 1 12:44:34 EDT 2010
On 10/1/2010 5:56 AM Antoon Pardon said...
> Someone provides you with a library of functions that act on sequences.
> They rely on the fact that '+' concatenates.
>
> Someone else provides you with a library of functions that act on
> numbers. They rely on the fact that '+' provides addition.
>
But you can do that now -- you just can't have a class that provides
_both_ behaviors.
>>> class Addem:
... def __init__(self,val):
... self.val = val
... def __add__(self,other):
... return self.val + other
...
>>> class Concatem:
... def __init__(self,val):
... self.val = val
... def __add__(self,other):
... return "%s%s" % (self.val,other)
...
>>>
>>> a = Addem(7)
>>> a+4
11
>>>
>>> b = Concatem(7)
>>> b+4
'74'
Emile
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