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

b.通过attr相关⽅方法去获取、修改、添加和删除它的属性

class Computer:
    def __init__(self, brand, colour='black', memsize='8G'):
        self.brand = brand
        self.colour = colour
        self.memsize = memsize

    def func1(self):
        print('%s可以打游戏,写代码，看视频' % self.brand)


c1 = Computer('联想')
print('c1:', c1)
c1.func1()
# 获取
print(c1.colour)
getattr(c1, 'colour')
# 修改
c1.memsize = '16G'
setattr(c1, 'memsize', '16G')
# 添加
c1.price = '$600'
setattr(c1, 'price', '$600')
# 删除
del c1.colour
delattr(c1, 'colour')

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.创建⼈的对⼩小明，让他拥有一条狗大⻩，然后让小明去遛大黄

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

    def cry(self):
        print('%s在叫唤' % self.name)


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

    def walk_dog(self):
        print('%s在遛%s' % (self.name, self.dog))


dog1 = Dog('大黄', '黄色', 2)
man1 = Man('小明', 18, dog1.name)
man1.walk_dog()

3.声明一个圆类，自己确定有哪些属性和方法

class Circle:
    pi = 3.1415926

    def __init__(self, radii, colour, name):
        self.radii = radii
        self.colour = colour
        self.name = name

    @classmethod
    def func2(cls, radii, name):
        area = cls.pi * radii**2
        perimeter = 2 * cls.pi * radii
        print('%s的面积是%s' % (name, area))
        print('%s的周长%s' % (name, perimeter))


yuan1 = Circle(3, 'black', '圆1')
yuan1.func2(yuan1.radii, yuan1.name)

4.创建⼀个学⽣生类:

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

import random


class Student:
    def __init__(self, name, age=0, study_id='000'):
        self.name = name
        self.age = age
        self.study_id = study_id
        self.is_in_class = random.randint(0, 1)

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

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


class Class:
    def __init__(self, name):
        self.students = []  
        self.name = name

        def func():
            num = 1
            while True:
                yield 'stu'+str(num)
                num += 1
        self.create_id = func()   

    def add_student(self):
        """添加学生"""
        name = input('学生姓名:')
        age = int(input('学生的年龄:'))
        study_id = next(self.create_id)
        stu = Student(name, age, study_id)
        self.students.append(stu)

    def del_student(self):
        """删除学生"""
        del_name = input('请输入要删除的学生的名字:')
        flag = False
        for stu in self.students[:]:
            if stu.name == del_name:
                flag = True
                stu.show()
                value = input('是否删除(y/n):')
                if value == 'y':
                    self.students.remove(stu)
        if not flag:
            print('没有该学生!')

    def call_name(self):
        """点名"""
        for stu in self.students:
            print(stu.name)
            if stu.is_in_class:
                stu.respond()

    def avg_age(self):
        """求平均年龄"""
        ages = 0
        for stu in self.students:
            ages += stu.age
        return ages / len(self.students)

    def show_all_students(self):
        print('=========%s的学生=========' % self.name)
        for stu in self.students:
            stu.show()


c1 = Class('py1906')
c2 = Class('py1907')
c1.add_student()    # 001
c1.add_student()    # 002
c2.add_student()    # 001
c1.add_student()    # 003
c1.show_all_students()
c2.show_all_students()
print(c1.avg_age())