Class takes no arguments (1 given) [duplicate]

问题

This question already has answers here:

Python interpreter error, x takes no arguments (1 given) (4 answers)

“<method> takes no arguments (1 given)” but I gave none (3 answers)

Python:Function takes no arguments (2 answers)

Closed 3 years ago.

class MyClass:
    def say():
        print("hello")

mc = MyClass()
mc.say()

I am getting error: TypeError: say() takes no arguments (1 given). What I am doing wrong?

回答1:

This is because methods in a class expect the first argument to be self. This self parameter is passed internally by python as it always sends a reference to itself when calling a method, even if it's unused within the method

class MyClass:
    def say(self):
        print("hello")

mc = MyClass()
mc.say()
>> hello

Alternatively, you can make the method static and remove the self parameter

class MyClass:
    @staticmethod
    def say():
        print("hello")

mc = MyClass()
mc.say()
>> hello

来源：https://stackoverflow.com/questions/46448875/class-takes-no-arguments-1-given