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方式获取、修改、添加和删除它的属性

class Computer:

    def __init__(self, brand='', color='', ram=''):
        self.brand = brand
        self.color = color
        self.ram = ram

    def coding(self):
        print('coding~~~')

    def wvideo(self):
        print('watching')

# 对象点
c1 = Computer('dell', 'grey', '16')
# 查
print(c1.brand)
# 修改
c1.color = 'pink'
print(c1.color)
# 添加
c1.price = '15000'
print(c1.price)
# 删除
print(c1.ram)
del c1.ram
print(c1.ram)

b.通过attr相关⽅方法去获取、修改、添加和删除它的属性  
# 查
getattr(c1, 'brand')
print(c1.brand)
# 修改
setattr(c1, 'color', 'pink')
print(c1.color)
# 添加
setattr(c1, 'price', '15000')
print(c1.price)
#删除
delattr(c1, 'ram')
# print(c1.ram)

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、年年龄、狗

人的方法:遛狗

a.创建⼈人的对象小明，让他拥有⼀一条狗大黄，然后让小明去遛大黄

class Dog:
    def __init__(self, name='', color='', age=''):
        self.name = name
        self.color = color
        self.age = age
    def bark(self):
        print('嗷呜~~~')

d1 = Dog(name='大黄')


class  People:
    def __init__(self, name='', age='', pet=''):
        self.name = name
        self.age = age
        self.pet = pet

    def walk_dog(self):
        print('%s溜%s' % (p1.name, p1.pet))


p1 = People(name='小明', pet='大黄')
p1.walk_dog()

3.声明⼀一个圆类，自己确定有哪些属性和方法

pi = 3.1415926


class Circle:

    def __init__(self, radius = 0):
        self.radius = radius

    def area(self):
        print(pi * self.radius ** 2)

    def perimeter(self):
        print(2*pi*self.radius)


c1 = Circle(5)
c1.area()
c1.perimeter()

4.创建⼀一个学⽣生类:

属性:姓名，年龄，学号

方法:答到，展示学⽣生信息

创建⼀一个班级类:

属性:学⽣生，班级名

方法:添加学⽣生，删除学生，点名, 求班上学生的平均年龄

import random


class Student:
    def __init__(self, name, age=0, num='0001'):
        self.name = name
        self.age = age
        self.num = num
        self.state = random.randint(0, 1)    # 是否在教室的状态， 0 -> 不在, 1 -> 在

    def amount(self):
        print('%s 到!' % self.name)

    def show(self):
        print('姓名:%s 年龄:%d 学号:%s' % (self.name, self.age, self.num))


class Class:
    def __init__(self, name):
        self.students = [
            Student('stu1', 19, '001'),
            Student('stu2', 20, '002'),
            Student('stu3', 23, '003'),
            Student('stu1', 19, '004'),
            Student('stu4', 30, '005'),
        ]
        self.name = name
        # 学号生成器
        self.__nums = ('stu'+str(num).zfill(3) for num in range(50))

    # 添加学⽣生
    def add_student(self):
        # 输入学生信息
        stu_name = input('姓名:')
        stu_age = int(input('年龄:'))
        stu_num = next(self.__nums)
        # 创建学生对象
        stu = Student(stu_name, stu_age, stu_num)
        # 将学生添加到班级中
        self.students.append(stu)

    # 删除学生
    def del_student(self):
        del_name = input('删除学生的姓名:')
        for stu in self.students[:]:
            if stu.name == del_name:
                self.students.remove(stu)

    # 点名
    def call_the_roll(self):
        for stu in self.students:
            # 喊名字
            print(stu.name)
            # 如果在教室
            if stu.state:
                # 答到
                stu.amount()
            else:
                print('....')

    def average_age(self):
        sum1 = 0
        for stu in self.students:
            sum1 += stu.age
        average = sum1//len(self.students)
        print('平均年龄: %d' % average)
        return average

    def cl_show(self):
        for stu in self.students:
            stu.show()


class1 = Class('py1902')

print('=========添加学生===========')
# for _ in range(5):
class1.add_student()
class1.cl_show()
print('=========删除学生===========')
class1.del_student()
class1.cl_show()
print('=========点名===========')
class1.call_the_roll()
class1.average_age()