What is the difference between decorators @staticmethod and @classmethod

The difference between decorators @staticmethod and @classmethod is: @staticmethod does not require self and cls parameters, @classmethod does not require self parameters, but requires cls parameters.

Generally speaking, when we use a method of a class, we must first instantiate the class, and then use the instantiated class to call its method

class Test(object):
    """docstring for Test"""
    def __init__(self, arg=None):
        super(Test, self).__init__()
        self.arg = arg
    def say_hi(self):
        print 'hello wrold'
def main():
    test = Test() //1. 首先实例化test类
    test.say_hi() //2. 再调用类的方法
if __name__ == '__main__':
    main()

When using @staticmethod or @classmethod, you can call it directly by class name.method name () without instantiation.

This helps organize the code, put certain functions that should belong to a certain class into that class, and also helps keep the namespace tidy.

class Test(object):
    """docstring for Test"""
    def __init__(self, arg=None):
        super(Test, self).__init__()
        self.arg = arg
    def say_hi(self):
        print 'hello wrold'
    @staticmethod
    def say_bad():
        print 'say bad'
    @classmethod
    def say_good(cls):
        print 'say good'
def main():
    test = Test()
    test.say_hi()
    Test.say_bad() //直接类名.方法名()来调用
    Test.say_good() //直接类名.方法名()来调用
if __name__ == '__main__':
    main()

The difference between @staticmethod or @classmethod

is an ordinary method of a class, and one parameter requires the self parameter to represent itself.

@staticmethod does not need to represent the self of its own object and the cls parameter of its own class, just like using a function.

@classmethod does not require the self parameter, but the first parameter needs to be the cls parameter representing its own class.

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