Python3类之六

###嵌套类##类的属性太多了##则可以使用嵌套的类

class Car():
    """一次模拟汽车的简单尝试"""
    def __init__(self,make,model,year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0
    def get_descriptive_name(self) :
        long_name = str(self.year) + " " + self.make + ' ' + self.model
        return long_name.title()
    def read_odometer(self):
        print ("This car has " +str(self.odometer_reading) + " miles on it .")
    def update_odometer(self,mileage) :
        if mileage >= self.odometer_reading :
            self.odometer_reading = mileage
        else :
            print ("You can't roll back an odometer !")
    def increment_odometer(self,miles) :
        self.odometer_reading += miles
    def fill_gas_tank(self) :
        print ("You need fill soil to gas tank!!!")

class Battery():
    """一次模拟电瓶的简单的尝试"""
    def __init__(self,battery_size=70) : 
        self.battery_size = battery_size
    def decribe_battery(self) :
        print ("This car is has a " + str(self.battery_size) + "-kWh battery .")
    
    

class ElectricCar(Car) :
    '''电动汽车的独特之处'''
    def __init__(self,make,model,year) :
        '''初始化父类的属性'''
        super().__init__(make,model,year)
        self.battery = Battery()
my_tesla = ElectricCar("tesla","model s",2017)
print (my_tesla.get_descriptive_name())
my_tesla.battery.decribe_battery()
################################################
#2017 Tesla Model S
#This car is has a 70-kWh battery .