Python中的super()面向对象编程

class A:
    def __init__(self):
        self.n = 1

    def add(self, m):
        print(f'AAA [self] is {id(self)}')
        print(f'AAA [self.n] is {self.n}')
        self.n += m


class B(A):
    def __init__(self):
        self.n = 100

    # 重写父类方法
    def add(self, m):
        # 子类特有代码
        print(f'BBB [self] is {id(self)}')
        print(f'BBB [self.n] is {self.n}')

        # 调用父类方法
        super().add(m)

        self.n += m


b = B()
b.add(2)
print(b.n)

 

# 输出结果
BBB [self] is 4489158560
BBB [self.n] is 100

AAA [self] is 4489158560
AAA [self.n] is 100

104

class Animal:
    def __init__(self, name):
        self.name = name

    def prints(self):
        print("Animale name is ", self.name)


class Dog(Animal):
    def __init__(self, name, age):
        # 调用父类的 init 构造方法
        super(Dog, self).__init__(name)
        self.age = age

    def prints(self):
        # 调用父类的方法
        super(Dog, self).prints()
        print("Dog age is ", self.age)


dog = Dog("小汪", 10)
dog.prints()

 

# 输出结果
Animale name is  小汪
Dog age is  10

class Animal:
    def __init__(self, name):
        self.name = name

    def prints(self):
        print("Animale name is ", self.name)


class Dog(Animal):
    def __init__(self, name, age):
        # 调用父类的 init 构造方法
        Animal.__init__(self, name)
        self.age = age

    def prints(self):
        # 调用父类的方法
        Animal.prints(self)
        print("Dog age is ", self.age)


dog = Dog("小汪", 10)
dog.prints()


# 输出结果
Animale name is  小汪
Dog age is  10

from threading import Thread


class MyThread(Thread):
    def __init__(self, name):
        # 1、实现子类独有功能
        print("子类线程 %s" % name)
        # 2、需要依赖父类方法完成其他功能
        super().__init__(name=name)

# 多继承
class Animal:
    def __init__(self, animalName):
        print(animalName, 'is an animal.')


# Mammal 继承 Animal
class Mammal(Animal):
    def __init__(self, mammalName):
        print(mammalName, 'is a mammal.')
        super().__init__(mammalName)


# CannotFly 继承 Mammal
class CannotFly(Mammal):
    def __init__(self, mammalThatCantFly):
        print(mammalThatCantFly, "cannot fly.")
        super().__init__(mammalThatCantFly)


# CannotSwim 继承 Mammal
class CannotSwim(Mammal):
    def __init__(self, mammalThatCantSwim):
        print(mammalThatCantSwim, "cannot swim.")
        super().__init__(mammalThatCantSwim)


# Cat 继承 CannotSwim 和 CannotFly
class Cat(CannotSwim, CannotFly):
    def __init__(self):
        print('I am a cat.');
        super().__init__('Cat')


# Driver code
cat = Cat()
print('')
bat = CannotSwim('Bat')

 

# 输出结果
I am a cat.
Cat cannot swim.
Cat cannot fly.
Cat is a mammal.
Cat is an animal.

Bat cannot swim.
Bat is a mammal.
Bat is an animal.

print(Cat.__mro__)

(<class '__main__.Cat'>, <class '__main__.CannotSwim'>, <class '__main__.CannotFly'>, <class '__main__.Mammal'>, <class '__main__.Animal'>, <class 'object'>)

class A:
    def __init__(self):
        self.n = 2

    def add(self, m):
        # 第四步
        # 来自 D.add 中的 super
        # self == d, self.n == d.n == 5
        print('self is {0} @AAA.add'.fORMat(self))
        self.n += m
        # d.n == 7


class C(A):
    def __init__(self):
        self.n = 4

    def add(self, m):
        # 第三步
        # 来自 B.add 中的 super
        # self == d, self.n == d.n == 5
        print('self is {0} @CCC.add'.format(self))
        # 等价于 suepr(C, self).add(m)
        # self 的 MRO 是 [D, B, C, A, object]
        # 从 C 之后的 [A, object] 中查找 add 方法
        super().add(m)

        # 第五步
        # d.n = 7
        self.n += 4
        # d.n = 11


class B(A):
    def __init__(self):
        self.n = 3

    def add(self, m):
        # 第二步
        # 来自 D.add 中的 super
        # self == d, self.n == d.n == 5
        print('self is {0} @BBB.add'.format(self))
        # self 的 MRO 是 [D, B, C, A, object]
        # 从 B 之后的 [C, A, object] 中查找 add 方法
        # 从 C 找 add 方法
        super().add(m)

        # 第六步
        # d.n = 11
        self.n += 3
        # d.n = 14


class D(B, C):
    def __init__(self):
        self.n = 5

    def add(self, m):
        # 第一步
        print('self is {0} @DDD.add'.format(self))
        # self 的 MRO 是 [D, B, C, A, object]
        # 从 D 之后的 [B, C, A, object] 中查找 add 方法
        # 从 B 找 add 方法
        super().add(m)

        # 第七步
        # d.n = 14
        self.n += 5
        # self.n = 19


d = D()
d.add(2)
print(d.n)
 

print(D.__mro__)

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

self is <__main__.D object at 0x10c14a190> @DDD.add
self is <__main__.D object at 0x10c14a190> @BBB.add
self is <__main__.D object at 0x10c14a190> @CCC.add
self is <__main__.D object at 0x10c14a190> @AAA.add
19

class D(B, C):          class B(A):            class C(A):             class A:
def add(self, m):       def add(self, m):      def add(self, m):       def add(self, m):
super().add(m)  1.--->  super().add(m) 2.--->  super().add(m)  3.--->  self.n += m
 self.n += 5   <------6. self.n += 3    <----5. self.n += 4     <----4. <--|
(14+5=19)               (11+3=14)              (7+4=11)                (5+2=7)