Py003-01-04组合

继承是类与类之间的关系

组合

先看这样一段代码 老师和学生

  • 有共用的属性 school
  • 有重复的属性 name,age,sex
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class Teacher:
    school = '中科院'

    def __init__(self,name,age,sex,level,salary):
        self.name = name
        self.age = age
        self.sex = sex
        
        self.level = level
        self.salary = salary

    def teach(self):
        print('%s is teaching'%self.name)


class Student:
    school = '中科院'
    def __init__(self,name,age,sex,classname):
        self.name = name
        self.age = age
        self.sex = sex

        self.classname = classname

    def learn(self):
        print('%s is learning'%self.name)

提取公共

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class People:
    school = '中科院'
    def __init__(self, name, age, sex):
        self.name = name
        self.age = age
        self.sex = sex


class Teacher(People):
    def __init__(self,name,age,sex,level,salary):
        super().__init__(name,age,sex)
        self.level = level
        self.salary = salary

    def teach(self):
        print('%s is teaching'%self.name)


class Student(People):
    def __init__(self,name,age,sex,classname):
        super().__init__(name, age, sex)
        self.classname = classname

    def learn(self):
        print('%s is learning'%self.name)

老师有课程，如果都教 python呢？

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class Teacher(People):
    def __init__(self,name,age,sex,level,salary,course_name,course_price,course_period):
        super().__init__(name,age,sex)
        self.level = level
        self.salary = salary
        self.course_name = course_name
        self.course_price = course_price
        self.course_period = course_period

# 这样就又重复了 俩个老师都教 python
t1 = Teacher('阮老师',49,'man',10,3000,'python',30000,'半年')
t2 = Teacher('廖雪峰',59,'man',10,3000,'python',30000,'半年')

继续提取课程 类

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class Course:
    def __init__(self,course_name,course_price,course_period):
        self.course_name = course_name
        self.course_price = course_price
        self.course_period = course_period

python = Course('python',30000,'半年')

此时老师和课程的关系？
  • 继承的关系是？——什么是什么
  • 组合呢？——什么有什么 如：老师有课程 学生有课程
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t1 = Teacher('阮老师',49,'man',10,3000)
t2 = Teacher('廖雪峰',59,'man',10,3000)   

t1.course = python
t2.course = python

# 访问t1/t2老师的课程名称
t1.course.course_name
t2.course.course_name

这种方式不是继承而是组合