Class Inheritance With Parameters That Have Defaults

Question

class test(int):
    def __init__(self, x, y=1):#y defaults to 1
        self.x=x
        self.y=y
    def __new__(cls, x, y):
        return int.__new__(cls, x+y)

test(2,3)#Is equal to 5
test(2)#Should equal 3 but __new__ (and other defs) ignore y=1.

I know you can do this with a normal function, but it is just an example. However, I need to inherit from a class and I don't like using *args (unless you can convince me to like them..). So how can I get y to default to some value?

That's exactly what I meant ^__^ ! I can't believe I didn't think of trying that... thank you. — what
– what, Commented Jan 27, 2010 at 18:26
Super! Not that it's going to get selected, so it will still show up as "Unanswered" but at least it has an answer now. :) — Lennart Regebro
– Lennart Regebro, Commented Feb 20, 2011 at 11:20

kennytm · Accepted Answer · 2011-02-20 08:14:44Z

4

Put the default parameter on __new__.

class test(int):
    def __new__(cls, x, y=1):
        ....

answered Feb 20, 2011 at 8:14

kennytm

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