How can I make a class that can be converted into an int?

Peter Otten __peter__ at web.de
Mon Oct 2 17:14:35 CEST 2006


Matthew Wilson wrote:

> What are the internal methods that I need to define on any class so that
> this code can work?
> 
> c = C("three")
> 
> i = int(c) # i is 3
> 
> I can handle the part of mapping "three" to 3, but I don't know what
> internal method is called when int(c) happens.

>>> class C(object):
...     def __int__(self): return 42
...
>>> int(C())
42

> For string conversion, I just define the __str__ method.  What's the
> equivalent for int?  For float, too, while I'm at it?

http://docs.python.org/ref/numeric-types.html

Peter



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