第六周 day6 python学习笔记

1.Python面向对象编程OOP(Object Oriented Programming)

封装:可以隐藏实现细节,使代码模块化

继承:可以扩展已存在的代码模块,可以使代码实现重用

多态:一种接口,多种实现,实现接口重用,为了类在继承和派生的时候,保证家谱中任一类的实例的某一属性的正确调用。

python不支持多态,但可以间接实现。

# 新式类与经典类的差别主要在多继承的顺序问题
# class People: #经典类的写法
class People(object): # 新式类的写法
    cn="中国"#类变量,大家公共的属性,节省内存开销
    def __init__(self,name,age):#构造函数,在实例化时做一些类的初始化的工作
        self.name=name#实例变量(静态变量),作用域就是实例本身
        self.age=age
        self.lover=[]

    def eat(self):#类的方法,功能(动态属性)
        print("%s is eating......"%self.name)

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

    def __del__(self):#析构函数:在实例释放、销毁的时候自动执行,通常用于做一些收尾的工作,如关闭一些数据库连接,打开的临时文件
        print("deleting %s"%self.name)

class Animal(object):
    def walk(self):
        print('%s is able to walk.'%self.name)
    def make_love(self,obj):
        print('%s is making love with %s'%(self.name,obj.name))
        self.lover.append(obj)

# python中可以实现多继承,先后继承的还是有顺序的
class Man(People,Animal):
    def __init__(self,name,age,property,education):#子类中重构父类的构造方法
        # People.__init__(self,name,age,education)
        super(Man,self).__init__(name,age)#这是新式类的写法,两种写法都可以的,下面这种更好,
        self.property=property
        self.__education=education#私有属性,定义时用__property样式,
        print('%s一出生就拥有%d元'%(self.name,self.property))

    # 定义一个显示教育信息的方法
    def show_edu(self):
        print("%s education :%s"%(self.name,self.__education))

    def runfast(self):#在子类中添加新的方法
        print("%s is running fast...."%self.name)
    def sleep(self):
        People.sleep(self)#执行父类的方法
        print("Man is sleeping,,,,,")#添加新的功能

class Woman(People,Animal):
    def born(self):
        print("%s is borning a baby,,,,"%self.name)


m1=Man("Jack",22,10000,"大学本科")
#print(m1.__education)#会报错,私有属性不能这么访问,
m1.show_edu()#通过函数进行访问
m1.sleep()

w1=Woman("Rose",18)
w1.sleep()
m1.make_love(w1)
w1.name='Roseenrr'
print('%s has lover : %s'%(m1.name,m1.lover[0].name))
w1.born()

面向对象
#python2.x中多继承:经典类按深度优先继承,新式类按广度优先继承的
#python3.x中多继承:都统一采用的广度优先继承
#多继承实例,B,C继承A,D继承B、C
class A(object):
    # pass
    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")

d1=D()#构造函数__init__()只构造一次,搜索顺序:D自身-->B--->C--->A
多继承
class School(object):
    def __init__(self,name,addr):
        self.name=name
        self.addr=addr
        self.students=[]
        self.teachers=[]

    def enroll(self,stu_obj):
        print("正在为学员%s办理入学注册手续"%stu_obj.name)
        self.students.append(stu_obj)

    def hire(self,staff_obj):
        print("雇佣新的教职工:%s"%staff_obj.name)
        self.teachers.append(staff_obj)

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):
        super(Teacher,self).__init__(name,age,sex)
        self.salary=salary
        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 缴费了 %s元'%(self.name,amount))
# 对象实例化
school=School("SMU","Shanghai")

teacher1=Teacher("Jackson",48,'M',15000,"C语言")
teacher2=Teacher("Jack",55,'M',18000,"python语言编程")

s1=Student("Jean",22,'M',2017001,"2班")
s2=Student("Alice",18,'F',2017002,"1班")

s1.tell()
s2.tell()
school.hire(teacher1)
school.hire(teacher2)
school.enroll(s1)
school.enroll(s2)
print(school.students)
print(school.teachers)

school.teachers[0].teach()
for stu in school.students:
    stu.pay_tuition(5000)
View code
#多态的实例
class Animal(object):
    def __init__(self,name):
       self.name=name

    def howl(self):
        pass
    #实现多态的方法
    @staticmethod
    def animal_howl(obj):
        obj.howl()

class Cat(Animal):
    def howl(self):
        print("Meow,Meow...")

class Dog(Animal):
    def howl(self):
        print("WOw,Wow,Wow")
c=Cat("Tom")
d=Dog("Wory")

Animal.animal_howl(c)#同样的方法,传入不同的对象,执行不同的方法
Animal.animal_howl(d)
多态

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