作业011：面向对象1

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, color = '黑色', memory = 8, weight=2):
        self.brand = brand
        self.color = color
        self.memory = memory
        self.weight = weight

    def game(self):
        pass

    def write_code(self):
        pass

    def look_video(self):
        pass

computer = Computer('华硕')
# 1)通过对象点的方式获取、修改、添加和删除它的属性
# 获取
print(computer.brand)
# 修改
computer.color = '白色'
# 添加
computer.size = 14.7
# 删除
del computer.weight

# 2)通过attr相关⽅方法去获取、修改、添加和删除它的属性
# 获取
print(getattr(computer, 'brand'))
print(getattr(computer, 'color', '蓝色'))
# 修改
setattr(computer, 'brand', '联想')
# print(getattr(computer, 'brand'))
# 添加
setattr(computer, 'key', 'very good')
# 删除
delattr(computer, 'size')

# print(computer.__dict__)  # 查看对象属性

2.声明⼀个人的类和狗的类:

狗的属性:名字、颜⾊色、年龄；方法:叫唤
人的属性:名字、年年龄、狗；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, name, color='黄色', age='2'):
        self.name = name
        self.color = color
        self.age = age

    def cry_out(self):
        pass


class Peron:

    def __init__(self, name: str, age=13):
        self.name = name
        self.age = age
        self.dog = None

    def walk_dog(self):
        if self.dog:
            print('{}天天都喜欢去遛{}'.format(self.name, self.dog.name))
        else:
            print('没有狗')


p = Peron('小明')
p.dog = Dog('大黄')
p.walk_dog()

3.声明一个圆类，自己确定有哪些属性和方法

属性：半径；方法：求面积，求周长

class Point:

    def __init__(self, x, y):
        self.x = x
        self.y = y

    def distance(self, other):
        """
        求当前点到另一个点的距离
        :param other: 另一个点对象
        :return: 点与点的距离
        """
        a = self.x - other.x
        b = self.y - other.y
        return (a ** 2 + b ** 2) ** 0.5


class Round:
    pi = 3.1415927

    def __init__(self, radius: float, center: Point):
        self.radius = radius
        self.center = center

    def area(self):
        # 类的字段在使用的时候用类名加字段名
        return Round.pi * self.radius ** 2

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

    def center_distance(self, other):
        """
        求两个圆的圆心距
        :param other: 另外一个圆
        :return: 圆心距
        """
        # self.center = Ponit(2, 2) 第一个圆的圆心
        # other.center = Ponit(4, 4) 第一个圆的圆心
        return self.center.distance(other.center)


class Line:
    def __init__(self, start_point: Point, end_point: Point):
        self.start_point = start_point
        self.end_point = end_point

    def length(self):
        return self.start_point.distance(self.end_point)


r = Round(0, Point(2, 2))
print(r.center_distance(Round(10, Point(4, 4))))


line1 = Line(Point(100, 100), Point(0, 0))
print(line1.length())

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
创建⼀一个班级类:属性:学⽣，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

from random import randint


class Student:

    def __init__(self, name, stu_id='001', age=17):
        self.name = name
        self.age = age
        self.stu_id = stu_id
        self.is_in_classroom = randint(0, 1)

    def answer_to(self):
        if self.is_in_classroom == 1:
            print('%s 到' % self.name)

    def show(self):
        print('姓名：{}， 年龄：{}， 学号：{}'.format(self.name, self.age, self.stu_id))


class Class:

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

    def add_stu(self):
        """添加学生"""
        stu_name = input('姓名:')
        stu_age = input('年龄:')
        stu_id = input('学号:')
        new_stu = Student(stu_name, stu_id, int(stu_age))
        self.students.append(new_stu)

    def del_stu(self):
        """
        删除学生
        stu是学生对象
        """
        stu_id = input('请输入需要删除的学生的学号:')
        for stu in self.students[:]:
            if stu.stu_id == stu_id:
                self.students.remove(stu)
                break
        else:
            print('没有该学生')

    def roll_call(self):
        for stu in self.students:
            print(stu.name)
            stu.answer_to()

    def avg_stu(self):
        count = len(self.students)
        sum = 0
        for stu in self.students:
            sum += stu.age
        print('平均年龄 %.2f' % (sum / count))

    def sort_stu(self):
        self.students.sort(reverse=True, key=lambda item: item.age)

    def show_all_stu(self):
        for stu in self.students:
            stu.show()


cls = Class('Py1906')
for _ in range(5):
    cls.add_stu()  # 添加学生

print('====显示学生===')
cls.show_all_stu()  # 显示学生

print('====排序====')
cls.sort_stu()  # 排序
cls.show_all_stu()  # 显示学生

print('====点名====')
cls.roll_call()  # 点名

print('====平均年龄====')
cls.avg_stu()  # 平均年龄

print('====删除学生====')
cls.del_stu()  # 删除学生
cls.show_all_stu()  # 显示学生