Python面向对象——多重继承大揭秘

1如果如图所示使用多重继承，我们将看到什么

2我们看到了基类被执行了两次Baseclass

3代码验证吧

class BaseClass:

    num_base_calls = 0

    def call_me(self):

        print("Calling method on Based Class")

        self.num_base_calls += 1

class LeftSubclass(BaseClass):

    num_left_calls = 0

    def call_me(self):

        BaseClass.call_me(self)

        print("Calling method on Left Subclass")

        self.num_left_calls += 1

class RightSubclass(BaseClass):

    num_right_calls = 0

    def call_me(self):

        BaseClass.call_me(self)

        print("Calling method on Right Subclass")

        self.num_right_calls += 1

class Subclass(LeftSubclass, RightSubclass):

    num_sub_calls = 0

    def call_me(self):

        LeftSubclass.call_me(self)

        RightSubclass.call_me(self)

        print("Calling method on Subclass")

        self.num_sub_calls += 1

s = Subclass()

s.call_me()

print(s.num_sub_calls, s.num_left_calls, s.num_right_calls, s.num_base_calls)

4改进措施

5完美解决=基类执行了一次

6代码验证

class BaseClass:

    num_base_calls = 0

    def call_me(self):

        print("Calling method on Based Class")

        self.num_base_calls += 1

class LeftSubclass(BaseClass):

    num_left_calls = 0

    def call_me(self):

        # BaseClass.call_me(self)

        super().call_me()

        print("Calling method on Left Subclass")

        self.num_left_calls += 1

class RightSubclass(BaseClass):

    num_right_calls = 0

    def call_me(self):

        # BaseClass.call_me(self)

        super().call_me()

        print("Calling method on Right Subclass")

        self.num_right_calls += 1

class Subclass(LeftSubclass, RightSubclass):

    num_sub_calls = 0

    def call_me(self):

        # LeftSubclass.call_me(self)

        # RightSubclass.call_me(self)

        super().call_me()

        print("Calling method on Subclass")

        self.num_sub_calls += 1

s = Subclass()

s.call_me()

print(s.num_sub_calls, s.num_left_calls, s.num_right_calls, s.num_base_calls)

参考：本文参考学习《Python3 Object Oriented Programming》，根据自己理解改编，Dusty Phillips 著