传递函数中的对象作为参数的魔术方法？

Question

Is there any magic method that will invoke when I pass object as argument of function?

class Test:
    def __init__(self, a, b):
         self.a = a
         self.b = b
    def __???__(self):
         return (self.a, self.b)

test = Test(0, 1)

some_function(test) # I'd like to pass parameters (0, 1) here

Answer 1

No, arguments to functions are not treated special in any way. It's just another assignment (to the parameter names of the function).

If you need to treat a and b as separate arguments, make Test a sequence , then pass it in with the *sequence call syntax to expand the sequence to separate arguments. You can make it a sequence by making it an iterator type :

class Test:
    def __init__(self, a, b):
         self.a = a
         self.b = b
    def __iter__(self):
         return iter((self.a, self.b))

test = Test(0, 1)
some_function(*test)

Demo:

>>> def some_function(a, b):
...     print(f'a = {a!r}\nb = {b!r}')
...
>>> test = Test(0, 1)
>>> some_function(*test)
a = 0
b = 1