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

class Pc:
    """电脑"""

    def __init__(self, brand, colour, memory):
        self.brand = brand
        self.colour = colour
        self.memory = memory

    def game(self):
        pass

    def code(self):
        pass

    def video(self):
        pass

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

p = Pc('Thunderobot', '银色', '8g')  # 创建
print(p.colour)  # 查询
p.colour = '黑色'  # 修改
p.weight = '5kg'  # 添加
del p.weight  # 添加

b.通过attr相关方法去获取、修改、添加和删除它的属性

print(getattr(p, 'colour'))  # 查询
setattr(p, 'colour', '银色')  # 修改
setattr(p, 'weight', '5kg')  # 添加
del p.weight  # 删除

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

class Dog:
    """狗"""
    def __init__(self, name='unknow', colour='unknow', age='unknow'):
        self.dog_name = name
        self.dog_colour = colour
        self.dog_age = age

    def barking(self):
        print(self.dog_name, '：“汪汪汪！”')
        return

人的属性:名字、年龄、狗

人的方法:遛狗

class Person(Dog):
    """人"""
    def __init__(self, name, age, dog_name='unknow', dog_colour='unknow', dog_age='unknow'):
        Dog.__init__(self, dog_name, dog_colour, dog_age)
        self.name = name
        self.age = age

    def walk_dog(self):
        print('%s出门溜%s' % (self.name, self.dog_name))

a.创建人的对象小明，让他拥有一条狗大黄，然后让小明去遛大黄

person = Person('小明', '20', '大黄')
person.walk_dog()

3.声明一个圆类，自己确定有哪些属性和方法

import math
class Round:
    def __init__(self, radius: float):
        self.radius = radius

    def area(self):
        return self.radius * self.radius * math.pi

    def girth(self):
        return 2 * math.pi * self.radius

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

student = [{'姓名': '小明', '年龄': 18, '学号': '1'}]
class Student:
    def __init__(self, name, age):
        self.stu_name = name
        self.stu_age = age
        self.stu_id = str(len(students) + 1)
        students.append({'姓名': name, '年龄': age, '学号': self.stu_id})

    def say_yes(self):
        print(self.stu_name, '：“到！”')

    def ex_stu(self):
        print(self.stu_name, self.stu_age, self.stu_id)

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

students = [{'姓名': '小明', '年龄': 18, '学号': '1'}]
class Classes:

    def __init__(self, class_name):
        self.class_name = class_name
        self.students = students

    def add_stu(self, stu_name, stu_age: int):
        student = {'姓名': stu_name, '年龄': stu_age, '学号': str(len(students) + 1)}
        students.append(student)
        print('添加成功')

    def del_stu(self, stu_name='', stu_id=''):
        for stu_dic in students:
            if stu_name == stu_dic['姓名'] or stu_id == stu_dic['学号']:
                students.remove(stu_dic)
                print('删除成功')

    def say_yes(self, stu_name='', stu_id=''):
        for stu_dic in students:
            if stu_name == stu_dic['姓名'] or stu_id == stu_dic['学号']:
                print('Yes!')

    def ave_age(self):
        ages = 0
        for stu_dic in students:
            ages += stu_dic['年龄']
        return ages / len(students)