On Mon, 08 Feb 2010 21:59:18 +0100, Martin Drautzburg wrote: > Just for the hell of it ... > > I can easily define __plus__() with three parameters. If the last one is > optional the + operation works as expected. Is there a way to pass the > third argument to "+"
How do you give three operands to a binary operator? Binary operators only have two sides, a left and a right, so you can only fit two operands around them. Mathematicians solve this problem by using functions: add(a, b, c, d) In Python, you can do this: >>> class F: ... def __add__(self, other, foo=None): ... print self, other, foo ... return 1 ... >>> >>> F() + 3 <__main__.F instance at 0xb7f06f4c> 3 None 1 >>> F().__add__(3, 4) <__main__.F instance at 0xb7f06d8c> 3 4 1 but if you do, people will laugh and point at you in the street. *wink* -- Steven -- http://mail.python.org/mailman/listinfo/python-list
