面向对象之继承——python篇，,继承继承：让子类拥有

print(C.__mro__)

在调用方法时，按照__mro__的输出结果从左至右的顺序查找。

如果再当前类中找到方法，就直接执行，不再向下搜索。

如果没有找到，就顺序查找下一个类中是否有对应的方法，如果找到，就直接执行，不再继续向下搜索。

如果找到了最后一个类，依然没有找到方法，程序就会报错。

super(类, 对象)：? ?获取指定类的父类（对象必须是类的对象； 类默认指向当前类，对象默认是当前类的对象)

class A:    def show(self):        print(‘A‘)class B(A):    def show(self):        super(B, self).show()        print(‘B‘)class C(A):    def show(self):        super().show()        print(‘C‘)class D(B, C):    def show(self):        super().show()        print(‘D‘)# BDd = D()d.show()print(D.__mro__)"""ACBD(<class ‘__main__.D‘>, <class ‘__main__.B‘>, <class ‘__main__.C‘>, <class ‘__main__.A‘>, <class ‘object‘>)"""

mro扩展

class A:    def show(self):        print(‘A‘)class B(A):    def show(self):        super().show()        print(‘B‘)class C(A):    def show(self):        super().show()        print(‘C‘)class D(A):    def show(self):        super().show()        print(‘D‘)class E(B, C):    def show(self):        super().show()        print(‘E‘)class F(C, D):    def show(self):        super().show()        print(‘F‘)class G(F, E):    def show(self):        super().show()        print(‘G‘)print(G.__mro__)g = G()g.show()"""(<class ‘__main__.G‘>, <class ‘__main__.F‘>, <class ‘__main__.E‘>, <class ‘__main__.B‘>, <class ‘__main__.C‘>, <class ‘__main__.D‘>, <class ‘__main__.A‘>, <class ‘object‘>)ADCBEFG"""

对象相关的内置函数

身份运算符：判断两个对象是否相等 is

lass Person(object):    def __init__(self, name, age):        self.name = name        self.age = agep1 = Person(‘张三‘, 18)p2 = Person(‘张三‘, 18)p3 = p1print(p1 is p2)  # Falseprint(p1 is p3)  # True

isinstance：用来判断对象和类之间的关系

class Person(object):    def __init__(self, name, age):        self.name = name        self.age = ageclass Student(Person):    def __init__(self, name, age, score):        super(Student, self).__init__(name, age)        self.score = scoreclass Dog(object):    def __init__(self, name, color):        self.name = name        self.color = colorp = Person(‘tony‘, 18)s = Student(‘jack‘, 20, 90)d = Dog(‘旺财‘, ‘白色‘)print(isinstance(p, Person))  # True.对象p是由Person类创建出来的print(isinstance(s, Person))  # True.对象s是有Person类的子类创建出来的print(isinstance(d, Person))  # False.对象d和Person类没有关系

issubclass ：用来判断两个类之间的继承关系

class Person(object):    def __init__(self, name, age):        self.name = name        self.age = ageclass Student(Person):    def __init__(self, name, age, score):        super(Student, self).__init__(name, age)        self.score = scoreclass Dog(object):    def __init__(self, name, color):        self.name = name        self.color = colorprint(issubclass(Student, Person))  # Trueprint(issubclass(Dog, Person))  # False

运算符重载

python中使用每一个运算符，其本质就是在调用运算符对应的方法（每个运算符都会调用对应的方法）

某种类型的数据支不支持某个运算符，就看这个数据对应的类型中有没有实现运算符对应的方法

from copy import copyclass Person:    def __init__(self, name=‘‘, age=0):        self.name = name        self.age = age    # +    def __add__(self, other):        # self + other        return self.age + other.age    # *    def __mul__(self, other):        list1 = []        for _ in range(other):            list1.append(copy(self))        return list1    # <    # 注意：大于符号和小于符号实现其中一个另外一个也可以用    def __lt__(self, other):        return self.age < other.age    def __repr__(self):        return f‘{str(self.__dict__)}‘p1 = Person(‘乌曼巴‘, age=18)p2 = Person(age=30)print(p1 == p2)print(p1 + p2)print(p1 * 3)print(p1 > p2)"""False48[{‘name‘: ‘乌曼巴‘, ‘age‘: 18}, {‘name‘: ‘乌曼巴‘, ‘age‘: 18}, {‘name‘: ‘乌曼巴‘, ‘age‘: 18}]False"""# 写了__lt__可以直接使用排序方法persons = [Person(‘乌曼巴‘, 20), Person(‘你诚心‘, 18), Person(‘得分手‘, 28), Person(‘李四‘, 15)]persons.sort()print(persons)"""[{‘name‘: ‘李四‘, ‘age‘: 15}, {‘name‘: ‘你诚心‘, ‘age‘: 18}, {‘name‘: ‘乌曼巴‘, ‘age‘: 20}, {‘name‘: ‘得分手‘, ‘age‘: 28}]"""

面向对象之继承——python篇