python--继承

继承

继承是代码的重用

• 子类中即实现父类的方法,又实现自己的方法:
• super().父类方法名(参数(自传self))
• 父类名.父类方法名(参数)
• 子类以及子类实例化的对象 可以访问父类的任何方法或变量.

class People():
    def __init__(self, name, age):
        self.Name = name
        self.Age = age

    def eat(self):
        print('%s is eating...' % self.Name)

    def talk(self):
        print('%s is talking...' % self.Name)

    def sleep(self):
        print('%s is sleeping...' % self.Name)


class Man(People):  # 继承了People类，括号里面的 父类,基类,超类   括号外面的 子类,派生类.

    def sleep(self):  # 有相同的方法时调用自己的
        People.sleep(self)  # 调用了People的sleep方法
        super().sleep()  # 新式类的写法
        print('man is sleep...')


m1 = Man('jack', 24)
m1.eat()
m1.sleep()

结果：

jack is eating...
jack is sleeping...
jack is sleeping...
man is sleep...

例

# class People():#经典类
class People(object):  # 新式类
    def __init__(self, name, age):
        self.Name = name
        self.Age = age

    def eat(self):
        print('%s is eating...' % self.Name)

    def talk(self):
        print('%s is talking...' % self.Name)

    def sleep(self):
        print('%s is sleeping...' % self.Name)


class Man(People):  # 继承了People类
    def __init__(self, name, age, money):  # 必须将参数都写上
        # People.__init__(self,name,age)  # name和age用People的实例变量，经典类写法

        super(Man, self).__init__(name, age)  # name和age用People的实例变量，新式类写法

        self.money = money
        print('%s have %s' % (self.Name, self.money))


def sleep(self):  # 重构People类，有相同的方法时调用自己的
    People.sleep(self)  # 调用了People的方法
    print('man is sleep...')


class Woman(People):
    def birth(self):
        print('woman is birth...')


m1 = Man('jack', 24, 88888)
m1.eat()
m1.sleep()

m2 = Woman('bob', 22)
m2.birth()
m2.sleep()

结果：

jack have 88888
jack is eating...
jack is sleeping...
woman is birth...
bob is sleeping...

多继承

class People(object):  # 新式类
    def __init__(self, name, age):
        self.name = name
        self.Age = age

    def eat(self):
        print('%s is eating...' % self.name)

    def talk(self):
        print('%s is talking...' % self.name)

    def sleep(self):
        print('%s is sleeping...' % self.name)


class Friend(object):
    def make_friend(self, obj):  # 这里的obj为后面实例化的值，底下将 m1 实例化后传给了 obj
        print("%s is with %s" %(self.name, obj.name))  # obj.name=jack


class Man(People, Friend):  # 继承了People类
    def __init__(self, name, age, money):  # 必须将参数都写上
        # People.__init__(self,name,age)  # name和age用People的实例变量，经典类写法
        super(Man, self).__init__(name, age)  # name和age用People的实例变量，新式类写法
        self.money = money

    def sleep(self):  # 重构People类,有相同的方法时调用自己的
        People.sleep(self)  # 调用了People的方法
        print('man is sleep...')


class Woman(People, Friend):
    def birth(self):
        print('woman is birth...')


m1 = Man('jack', 24, 88888)
print(m1)
m2 = Woman('bob', 22)
m2.make_friend(m1)  # make_friend需要传一个值，将m1传给   make_friend

结果：

<__main__.Man object at 0x0320B430>
bob is with jack

Friend不用初始化，因为先继承people，里面有name，age，如果people和Friend换位置，也没事，因为Friend没有执行

类名.mro()查看类的继承顺序

class A:
    def __init__(self):
        print("A")


class B(A):
    pass
    # def __init__(self):
    #     print("B")


class C(A):
    # pass
    def __init__(self):
        print("C")


class D(B, C):
    pass
    # def __init__(self):
    #     print("D")


obj = D()

结果：

C

py2经典类是按深度优先来继承的，新式类是按广度优先来继承的

py3经典类和新式类统一是按广度优先来继承的

class School(object):
    def __init__(self, name, addr):
        self.name = name
        self.addr = addr
        self.students = []  # 定义了列表，放学生
        self.staffs = []  # 定义了列表，放老师

    def enroll(self, stu_obj):  # 学生注册
        print('为学员%s 办理注册手续' % stu_obj.name)
        self.students.append(stu_obj)  # 将学生加到列表里

    def hire(self, staff_obj):  # 雇佣老师，staff_obj实例化，这里是Teacher类
        print('雇佣新员工%s' % staff_obj.name)  # staff_obj.name是Teacher里的name
        self.staffs.append(staff_obj)  # 加到老师列表里


class SchoolMember(object):
    def __init__(self, name, age, sex):
        self.name = name
        self.age = age
        self.sex = sex

    def tell(self):
        pass


class Teacher(SchoolMember):
    def __init__(self, name, age, sex, salary, course):  # 先覆盖父类的

        super(Teacher, self).__init__(name, age, sex)  # 继承父类的name, age, sex

        self.salary = salary  # 添加新的属性
        self.course = course

    def tell(self):
        print('''
            -------info of Teacher:%s-------
            Name:%s
            Age:%s
            Sex:%s
            Salary:%s
            Course:%s
            ''' % (self.name, self.name, self.age, self.sex, self.salary, self.course))

    def teach(self):
        print('%s is teaching course [%s]' % (self.name, self.course))


class Student(SchoolMember):
    def __init__(self, name, age, sex, stu_id, grade):
        super(Student, self).__init__(name, age, sex)
        self.stu_id = stu_id
        self.grade = grade

    def tell(self):
        print('''  -------info of Student:%s-------
        Name:%s
        Age:%s
        Sex:%s
        Stu_id:%s
        Grade:%s
        ''' % (self.name, self.name, self.age, self.sex, self.stu_id, self.grade))

    def pay_tuition(self, amount):
        print('%s has paid tution $%s' % (self.name, amount))


school = School('高科', '西安')  # 实例化了School类
t1 = Teacher('lfj', 32, 'm', 3000, 'python')  # 实例化了Teacher类
t2 = Teacher('zouzou', 22, 'm', 30000, 'linuxDevops')
# 实例化了Teacher类
s1 = Student('jack', 36, 'mm', 1001, 'python')  # 实例化了Student类
s2 = Student('bob', 30, 'mm', 1002, 'linuxDevops')
# 实例化了 Student类
t1.tell()
s1.tell()
school.hire(t1)  # 将t1传给hire
school.enroll(s1)  # 将实例化了的Student类school下的enroll
school.enroll(s2)
print(school.students)  # 打印出学生的内存地址
print(school.staffs)  # 打印出老师的内存地址
school.staffs[0].teach()  # 调用了Teacher下的teach
for stu in school.students:
    stu.pay_tuition(5000)  # 调用了students下的pay_tuition

结果：

            -------info of Teacher:lfj-------
            Name:lfj
            Age:32
            Sex:m
            Salary:3000
            Course:python
            
  -------info of Student:jack-------
        Name:jack
        Age:36
        Sex:mm
        Stu_id:1001
        Grade:python
        
雇佣新员工lfj
为学员jack 办理注册手续
为学员bob 办理注册手续
[<__main__.Student object at 0x02C9B790>, <__main__.Student object at 0x02C9B7B0>]
[<__main__.Teacher object at 0x02C9B750>]
lfj is teaching course [python]
jack has paid tution $5000
bob has paid tution $5000