staticmethod classmethod修饰符

一、staticmethod(function)

Return a static method for function.
A static method does not receive an implicit first argument. To declare a static method, use this idiom:

class Sing():
    @staticmethod
    def sayHello():
        print "hello world"

    def sayNo():
        print "no"

if __name__ == '__main__':
    Sing.sayHello()
    Sing.sayNo()

Sing.sayNo报错如下：

TypeError: unbound method sayNo() must be called with Sing instance as first argument (got nothing instead)
sayNo()方法非静态方法，需要先将对象Sing实例化才能调用该方法
而sayHello()方法不报错，因为staticmethod修饰
下面方法才是对的：

class Sing():
    @staticmethod
    def sayHello():
        print "hello world"

    def sayNo(self):
        print "no"

if __name__ == '__main__':
    Sing.sayHello()
    sing = Sing()
    sing.sayNo()

二、classmethod(function)

Return a class method for function.
A class method receives the class as implicit first argument, just like an instance method receives the instance. To declare a class method, use this idiom:

class Sing():
    @classmethod
    def sayHello(self):
        print "hello world"

    def sayNo(self):
        print "no"

if __name__ == '__main__':
    Sing.sayHello()
    sing = Sing()
    sing.sayNo()
    

注意：staticmethod修饰的方法不需要接self参数，而classmethod修饰的方法则需要接self参数；

三、@property修饰符（新式类特有，新式类即接object定义的类）
修饰为类的属性，如下为不加@property修饰符的类的定义：

class C(object):
    def __init__(self):
        self._x = None

    def getx(self):
        return self._x
    def setx(self, value):
        self._x = value
    def delx(self):
        del self._x
    x = property(getx, setx, delx, "I'm the 'x' property.")

通过@property修饰符修饰的类的定义：（从Python2.6开始引入setter,deleter,getter属性）

class C(object):
    def __init__(self): self._x = None

    @property
    def x(self):
        """I'm the 'x' property."""
        return self._x

    @x.setter
    def x(self, value):
        self._x = value

    @x.deleter
    def x(self):
        del self._x