理解python super

不要一说到 super 就想到父类！super 指的是 MRO 中的下一个类！

class Root(object):
    def __init__(self):
        print("this is Root")
class B(Root):
    def __init__(self):
        print("enter B")
        # print(self)  # this will print <__main__.D object at 0x...>
        super(B, self).__init__()
        print("leave B")
class C(Root):
    def __init__(self):
        print("enter C")
        super(C, self).__init__()
        print("leave C")
class D(B, C):
    pass
d = D()
print(d.__class__.__mro__)

enter B
enter C
this is Root
leave C
leave B
(<class '__main__.D'>, <class '__main__.B'>, <class '__main__.C'>, <class '__main__.Root'>, <type 'object'>)

首先，我们获取 self.class.mro，注意这里的 self 是 D 的 instance 而不是 B 的

(<class '__main__.D'>, <class '__main__.B'>, <class '__main__.C'>, <class '__main__.Root'>, <type 'object'>)