第六节

类和方法

1.类的作用及析构函数

class role:
    def __init__(self,name,age,life_valie):　　#类的初始化变量
        self.name = name
        self.age = age
        self.__life_value = life_valie

    def __del__(self):
        print("this is 析构函数")

    def got_shot(self):
        self.__life_value -= 50　　#定义私有变量，只能在类的内部调用

    def show_life_value(self):　　　　
        print(self.__life_value)　　#私有变量可以通过调用某些方法来取出

r1=role("jack",18,100)
print(r1.name)
r1.got_shot()
r1.show_life_value()

运行结果：
jack
50
this is 析构函数


2.父类和子类

class people:
    def __init__(self,name,age):
        self.name = name
        self.age = age

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

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

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

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

m1=man("jack",25)
m1.sleep()
m2=woman("mary",24)
m2.sleep()
运行结果：
jack is sleeping
man jack is sleeping
woman mary is sleeping

3.经典类与新式类

#class people:   #经典类
class people(object):
    def __init__(self,name,age):
        self.name = name
        self.age = age

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

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

class man(people):
    def __init__(self,name,age,weight):
        #people.__init__(self,name,age)   #经典类
        super(man,self).__init__(name,age)  #新式类
        self.weight = weight
        print("%s 的年龄%s,体重%d" % (self.name,self.age,self.weight))
    def sleep(self):
        people.sleep(self)
        print("man %s is sleeping" % self.name)

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

m1=man("jack",25,30)
m1.sleep()
m2=woman("mary",24)
m2.sleep()

运行结果：
jack 的年龄25,体重30
jack is sleeping
man jack is sleeping
woman mary is sleeping

4.继承多个类

#class people:   #经典类
class people(object):
    def __init__(self,name,age):
        self.name = name
        self.age = age

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

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

class relationship(object):
    def make_friends(self,obj):
        print("%s is making friends with %s" % (self.name,obj.name))

class man(people,relationship):
    def __init__(self,name,age,weight):
        #people.__init__(self,name,age)   #经典类
        super(man,self).__init__(name,age)  #新式类
        self.weight = weight
        print("%s 的年龄%s,体重%d" % (self.name,self.age,self.weight))
    def sleep(self):
        people.sleep(self)
        print("man %s is sleeping" % self.name)

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

m1=man("jack",25,30)
m1.sleep()
m2=woman("mary",24)
m2.sleep()
m1.make_friends(m2)

运行结果：
jack 的年龄25,体重30
jack is sleeping
man jack is sleeping
woman mary is sleeping
jack is making friends with mary

5.深度优先与广度优先
python2类的继承为深度优先
python3类的继承为广度优先

6.继承
class School(object):
    def __init__(self,name,addr):
        self.name= name
        self.addr = addr
        self.students = []
        self.staffs = []

    def enroll(self,stu_obj):
        self.students.append(stu_obj)
        print("为新学生%s办理注册手续" % stu_obj.name)

    def hire(self,staf_obj):
        self.staffs.append(staf_obj)
        print("雇佣新员工%s" % staf_obj.name)

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

    def tell(self):
        pass

class Teacher(SchoolNumber):
    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----
        Name:%s
        Age:%s
        Sex:%s
        Salary:%s
        Course:%s
        ''' % (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(SchoolNumber):
    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 teacher----
        Name:%s
        Age:%s
        Sex:%s
        Stu_id:%s
        Grade:%s
        ''' % (self.name,self.age,self.sex,self.stu_id,self.grade))

    def pay_tuition(self,amount):
        print("%s has paid tuition for $%s" % (self.name,amount))


school = School("河北农业大学","保定")

t1=Teacher("tom",53,"male",10000,"Python")
t2=Teacher("jack",48,"female",10000,"Math")
s1=Student("panjiatao",25,"male",10001,"大四")
s2=Student("mary",22,"female",10002,"大二")

t1.tell()
s1.tell()
school.hire(t1)
school.enroll(s1)
school.enroll(s2)

print(school.students)  #两个列表
print(school.staffs)

school.staffs[0].teach()

for stu in school.students:
    stu.pay_tuition(5000)

运行结果：
        ----info of teacher----
        Name:tom
        Age:53
        Sex:male
        Salary:10000
        Course:Python
        

        ----info of teacher----
        Name:panjiatao
        Age:25
        Sex:male
        Stu_id:10001
        Grade:大四
        
雇佣新员工tom
为新学生panjiatao办理注册手续
为新学生mary办理注册手续
[<__main__.Student object at 0x000000304CC05080>, <__main__.Student object at 0x000000304CC050B8>]
[<__main__.Teacher object at 0x000000304CBF9FD0>]
tom is teaching course [Python]
panjiatao has paid tuition for $5000
mary has paid tuition for $5000

 多态