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, memsize):
        self.brand = brand
        self.color = color
        self.memsize = memsize
# 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


c1 = Computer('apple', '银色', '6G')
print(c1.brand)
c1.brand = '华硕'
print(c1.brand)
c1.screen_size = '15寸'
print(c1.screen_size)
del c1.color
# b.通过attr相关⽅方法去获取、修改、添加和删除它的属性
c2 = Computer('apple', '银色', '6G')
print(getattr(c2, 'brand'))
setattr(c2, 'color', '白色')
print(c2.color)
setattr(c2, 'screen_size', '16寸')
print(c2.screen_size)
delattr(c2, 'brand')

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.创建人的对象小明，让他拥有一条狗大黄，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 dog_call(self):
        print('%s在叫唤' % self.name)


d1 = Dog('大黄', '黄色', '12')


class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
        self.dog = None

    def walk_dog(self):
        if not self.dog:
            print('没有狗')
        else:
            print('%s正在遛%s' % (self.name, self.dog.name))


p1 = Person('小明', '25')
print(d1.name)
p1.dog = d1  # 让人拥有狗
print(p1.dog)
p1.walk_dog()

3.声明一个圆类，自己确定有哪些属性和方法

class Circle:
    pi = 3.14
    def __init__(self, radius):
        self.radius = radius

    def area(self):
        return Circle.pi*(self.radius**2)

    def perimeter(self):
        return 2*Circle.pi*self.radius


c1 = Circle(7)
print(c1.area())
print(c1.perimeter())

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, stu_id):
        self.name = name
        self.age = age
        self.stu_id = stu_id
        self.is_in_class = random.randint(0, 1)
        
    def responses(self):
        print('%s, 到' % self.name)

    def show(self):
        print('学生：%s， 年龄：%s， 学号：%s' % (self.name, self.age, self.stu_id))


class Class:
    def __init__(self, name):
        self.all_students = []
        self.name = name
        # self.count = 0

        def func():
            num = 1
            while True:
                yield 'stu'+str(num)
                num += 1
        self.create_id = func()
    def add_student(self):
        name = input('姓名：')
        age = input('年龄：')
        # self.count += 1
        # stu_id = 'stu'+str(self.count).rjust(3, '0')
        stu_id = self.create_id
        stu = Students(name, int(age), stu_id)
        self.all_students.append(stu)
        print('学生：%s， 年龄：%s， 学号：%s' % (name, age, stu_id))

    def show_all_students(self):
        for stu in self.all_students:
            stu.show()

    def delete(self):
        del_name = input('输入要删除学生姓名：')
        flag = False
        for stu in self.all_students[:]:
            if stu.name == del_name:
                stu.show()
                flag = True
                value = input('是否删除（y/n）:')
                if value == 'y':
                    self.all_students.remove(stu)
                    print('删除成功')
        if not flag:
            print('没有该学生')

    def call_name(self):
        for stu in self.all_students:
            print(stu.name)
            if stu.is_in_class:
                stu.responses()

    def average(self):
        sum1 = 0
        for stu in self.all_students:
            sum1 += int(stu.age)
        print('python1903的平均年龄为%s' % (sum1/len(self.all_students)))


class1 = Class('python1903')
for i in range(3):
    class1.add_student()
class1.delete()
class1.call_name()
class1.average()class Students:
    def __init__(self, name, age, stu_id):
        self.name = name
        self.age = age
        self.stu_id = stu_id
        self.is_in_class = random.randint(0, 1)
        
    def responses(self):
        print('%s, 到' % self.name)

    def show(self):
        print('学生：%s， 年龄：%s， 学号：%s' % (self.name, self.age, self.stu_id))


class Class:
    def __init__(self, name):
        self.all_students = []
        self.name = name
        # self.count = 0

        def func():
            num = 1
            while True:
                yield 'stu'+str(num)
                num += 1
        self.create_id = func()
    def add_student(self):
        name = input('姓名：')
        age = input('年龄：')
        # self.count += 1
        # stu_id = 'stu'+str(self.count).rjust(3, '0')
        stu_id = self.create_id
        stu = Students(name, int(age), stu_id)
        self.all_students.append(stu)
        print('学生：%s， 年龄：%s， 学号：%s' % (name, age, stu_id))

    def show_all_students(self):
        for stu in self.all_students:
            stu.show()

    def delete(self):
        del_name = input('输入要删除学生姓名：')
        flag = False
        for stu in self.all_students[:]:
            if stu.name == del_name:
                stu.show()
                flag = True
                value = input('是否删除（y/n）:')
                if value == 'y':
                    self.all_students.remove(stu)
                    print('删除成功')
        if not flag:
            print('没有该学生')

    def call_name(self):
        for stu in self.all_students:
            print(stu.name)
            if stu.is_in_class:
                stu.responses()

    def average(self):
        sum1 = 0
        for stu in self.all_students:
            sum1 += int(stu.age)
        print('python1903的平均年龄为%s' % (sum1/len(self.all_students)))


class1 = Class('python1903')
for i in range(3):
    class1.add_student()
class1.delete()
class1.call_name()
class1.average()