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

    def game(self):
        print(self.brand+'可以打游戏')

    def code(self):
        print(self.brand+'可以写代码')

    def video(self):
        print(self.brand+'可以看视频')


# 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
pc1 = Computer('华为', '黑色', '256G')
print(pc1.brand, pc1.color, pc1.memory)
pc1.brand = '联想'
pc1.seize = '15.6'
del pc1.seize

# b.通过attr相关⽅方法去获取、修改、添加和删除它的属性
print(getattr(pc1, 'brand'))
setattr(pc1, 'memory', '128G')
setattr(pc1, 'seize', '15.6')
delattr(pc1, 'seize')

2.声明⼀个人的类和狗的类:

# 狗的属性:名字、颜⾊色、年年龄
# 狗的⽅方法:叫唤
class Dog:
    def __init__(self, name, color, age):
        self.name= name
        self.color = color
        self.age = age

    def bark(self):
        print(self.name+'在叫')


# 人的属性:名字、年年龄、狗
# 人的⽅方法:遛狗
class Person:
    def __init__(self, name, age, dog:Dog):
        self.name = name
        self.age = age
        self.dog = dog

    def walk_a_dog(self):
        if self.dog:
            print(self.name+'正在遛'+self.dog.name)
        else:
            print('没有狗')


# a.创建⼈人的对象⼩小明，让他拥有⼀一条狗⼤大⻩黄，然后让⼩小明去遛⼤大⻩黄
d1 = Dog('大黄', '黄色', 2)
p1 = Person('小明', 18, d1)
p1.walk_a_dog()

3.声明⼀一个圆类，自己确定有哪些属性和方法

class Circular:
    Pai = 3.14

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

    def perimeter(self):
        per = self.radius*Circular.Pai*2
        return per

    def area(self):
        are = Circular.Pai*(self.radius**2)
        return are


c1 = Circular(2)
print(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

class Student:

    def __init__(self, name, age, stu_id):
        self.name = name
        self.age = age
        self.stu_id = stu_id
        self.attendence = random.randint(0, 1)

    def answer(self):
        if self.attendence == 0:
            print('该生未到')
        else:
            print(self.name+'到了！')


stu1 = Student('xiaoming', 18, '001')
print(stu1.attendence)
stu1.answer()

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

class Classes:

    def __init__(self, class_name):
        self.class_name = class_name
        self.student = []

    def add_student(self, student: Student):
        stu_dic = student.__dict__
        self.student.append(stu_dic)

    def delete_student(self, stu_id: str):
        for stu_dic in self.student:
            if stu_dic['stu_id'] == stu_id:
                self.student.remove(stu_dic)
                break
        else:
            print('没有该学生!')

    def class_answer(self, student_name: str):
        for stu_dic in self.student:
            if student_name == stu_dic['name']:
                if stu_dic['attendence'] == 0:
                    print(student_name+'没有到')
                    break
                else:
                    print(student_name+'到了')
                    break
        else:
            print('没有该生'+student_name)

    def aver_age(self):
        sum_age = 0
        for stu_dic in self.student:
            sum_age += stu_dic['age']
        print('平均年龄是：%.2f' % (sum_age / len(self.student)))