2019-01-11day15课后作业

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 ='苹果',color='黑色',internal_storage='4G'):
        self.brand = brand
        self.color = color
        self.internal_storage = internal_storage

    def paly(self):
        print('%s可以打游戏' % self)

    def write_code(self):
        print('%s可以写代码' % self)

    def watch_movies(self):
        print('%s可以看电影' % self)


computer = Computer()
computer.brand = '联想'
computer.color = '绿色'
computer.internal_storage = '18T'
getattr(computer, 'brand',None)
print(computer.brand)
print(computer.color)
print(computer.internal_storage)
computer.system = 'windows7'
del computer.brand
del computer.color
delattr(computer, 'inter_storage')
delattr(computer, 'system')

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 人的属性:名字、年年龄、狗 人的⽅方法:遛狗 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

class Dog:
    def __init__(self,name1='老王',color1='绿色',age1=19):
        self.name = name1
        self.color = color1
        self.age = age1

    def bark(self):
        print('%s在叫' % self)


class Human:
    def __init__(self,name,dog, age=18):
        self.name = name
        self.age = age
        self.dog = dog

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


person = Human('小明','大黄')
person.walk_a_dog()

3.声明⼀一个圆类:

class Circle:
    nun1 = 3.14

    def __init__(self,radius: float):
        self.radius = radius
        self.n = 3.14

    def area(self):
        return self.n * self.radius ** 2

    def circumference(self):
        return 2 * self.n * self.radius

    def diameter(self):
        return 2 * self.radius

circle = Circle(4)
print(circle.area())

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 Students:
    def __init__(self, name, age, id):
        self.name = name
        self.age = age
        self.id = id

    def answer(self):
        print('到！我是%s今年%d岁学号是%s' % (self.name, self.age, self.id))


stu = Students('小明',18,'stu0001')
stu.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

def file_read_json(file_name):
    try:
        with open('files/'+file_name, 'r', encoding='utf-8') as f:
            return json.load(f)
    except (FileNotFoundError, IsADirectoryError):
        print('%s不存在' % file_name)


def file_write_json(file_name, content):
    try:
        with open('files/'+file_name, 'w', encoding='utf-8') as f:
            return json.dump(content, f)
    except(FileNotFoundError, IsADirectoryError):
        print('%s不存在' % file_name)


class Student:
    def __init__(self, name, age, id1):
        self.name = name
        self.age = age
        self.id = id1

    def answer(self):
        print('到！')


class Class:
    def __init__(self, class_name):
        self.class_name = class_name

    def add_student(self, student):
        # 提出所有信息的列表
        information = file_read_json('students_information.json')
        information.setdefault(self.class_name, [])
        students = information[self.class_name]
        students.append(student.__dict__)
        information[self.class_name] = students
        file_write_json('students_information.json',information)

    def del_student(self, student):
        information = file_read_json('students_information.json')
        students = information[self.class_name]
        for item in students:
            if item == student.__dict__:
                students.remove(student.__dict__)
                print('删除的学生为%s%s' % (self.class_name, student.__dict__))
                information[self.class_name] = students
                result = file_write_json('students_information.json', information)
                break
            else:
                print('没有该学生')

    def show_class_information(self, student):
        information = file_read_json('students_information.json')
        information.setdefault(self.class_name, [])
        students = information[self.class_name]
        for item in students:
            if item == student.__dict__:
                student.answer()
                break

    def average(self):
        information = file_read_json('students_information.json')
        information.setdefault(self.class_name, [])
        students = information[self.class_name]
        count = 0
        sum = 0
        for item in students:
            count += 1
            sum += item['age']
        print('全部学生的平均年龄为：%d' % (sum/count))


stu2 = Student('小明', 1, 'stu0001')
class1 = Class('2班')
class1.add_student(stu2)
class1.del_student(stu2)
class1.show_class_information(stu2)
class1.average()