class.py

class Dog():                            #创建类
    """一次模拟小狗的简单尝试"""
    def __init__(self,name,age):
        """初始化属性name和age"""
        self.name = name
        self.age = age

    def sit(self):
        """模拟小狗被命令时蹲下"""
        print(self.name.title()+ "is now sitting.")

    def roll_over(self):
        """模拟小狗被命令时打滚"""
        print(self.name.title()+"roll over!")


obj=Dog('whille', 6)                #根据类创建实例
print(obj.name)
obj.sit()
obj.roll_over()

class Car():                                    #Car类
    """一次模拟汽车的简单尝试"""
    def __init__(self,make,model,year,):
        """初始化描述汽车的属性"""
        self.make  = make
        self.model = model
        self.year = year
        self.odometer_reading = 0         #给属性指定默认值

    def get_descriptive_name(self):
        """返回整洁的信息"""
        long_name = str(self.year)+' '+self.make + ' '+self.model
        print(long_name)
        return long_name.title()

    def read_odometer(self):
        """打印一条指出汽车里程的信息"""
        print("This car has " + str(self.odometer_reading) + " miles on it ")

    def update_odometer(self, mileage):         #用方法修改属性的值
        self.odometer_reading = mileage
new_car = Car('audi','a4',2016)
new_car.get_descriptive_name()
new_car.odometer_reading = 23          #直接修改属性默认值
new_car.read_odometer()