1.声明一个电脑类：属性：品牌、颜色、内存大小 方法：打游戏、写代码、看视频

a.创建电脑类的对象,然后通过对象点的方式获取\修改\添加和删除它的属性

b.通过attr相关方法去获取\修改\添加和删除它的属性

class Computer:
    def __init__(self, brand, color, memory=4):
        self.brand = brand
        self.color = color
        self.memory = memory

    def play_game(self, game):
        print('用%s电脑玩%s' % (self.brand, game))

    def write_code(self):
        print('用%s电脑写代码' % self.brand)

    def watch_video(self):
        print('用%s电脑看视频' % self.brand)


computer1 = Computer('dell', 'black')
computer1.play_game('LOL')
computer1.CPU = 'i7 8500'
computer1.color = 'pink'
del computer1.CPU
print(getattr(computer1, 'brand', '没有品牌'))
setattr(computer1, 'memory', 8)
setattr(computer1, 'CPU', 'i7 8500')
delattr(computer1, 'CPU')

2.声明一个人的类和狗的类:

狗的属性:名字\颜色\年龄;狗的方法:叫唤

人的属性:名字\年龄\狗;人的方法:遛狗

a.创建人人的对象小明,让他拥有一条狗大黄,然后让小明去遛大黄

class Person:
    def __init__(self, name, age='', dog=None):
        self.name = name
        self.age = age
        if dog:
            self.dog = dog.name
        else:
            print('没有狗')

    def walk_the_dog(self):
        print('%s带着%s散步' % (self.name, self.dog))


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

    def bark(self):
        print('%s叫' % self.name)


dog1 = Dog('大黄', 'black', 4)
person = Person('小明', dog=dog1)
person.walk_the_dog()

3.声明一个圆类,自己确定有哪些属性和方法

import math


class Circle:
    def __init__(self, r):
        self.r = r

    def area(self):
        return math.pi * self.r ** 2

    def perimeter(self):
        return math.pi*self.r*2

4.创建一个学生类:

属性:姓名,年龄,学号

方法:答到,展示学生信息

创建一个班级类:

属性:学生,班级名

方法:添加学生,删除学生,点名,求班上学生的平均年龄

class Students:
    def __init__(self, name, age=None, student_numbers='0000'):
        self.name = name
        self.age = age
        self.student_numbers = student_numbers

    def answer_student(self):
        print('%s在教室' % self.name)
        print('1.在')
        print('2.不在')
        n = int(input('请输入:'))
        if n == 1:
            return True
        else:
            return False

    def student_information(self):
        print(self.name)
        print(self.age)
        print(self.student_numbers)


class Class:
    def __init__(self, class_name, students_list: list):
        self.class_name = class_name
        self.students_list = students_list

    def add_student(self):
        name = input('请输入姓名')
        age = int(input('请输入年龄'))
        student_numbers = input('请输入学生学号')
        stu = Students(name, age, student_numbers)
        self.students_list.append(stu)

    def del_student(self, name):
        for index in range(len(self.students_list)):
            if self.students_list[index].name == name:
                self.students_list.remove(self.students_list[index])
                break

    def call_student(self):
        for student in self.students_list:
            if student.answer_student():
                print('%s在' % student.name)
            else:
                print('%s不在' % student.name)
        return

    def average_age(self):
        sum_age = 0
        for student in self.students_list:
            sum_age += student.age
        return float(sum_age/len(self.students_list))