例题9-1 餐馆
描述:创建Restaurant 类,
init() 设置两个属性:restaurant_name 和cuisine_type 。
创建一个名为describe_restaurant() 的方法
和一个名为open_restaurant() 的方法,
其中前者打印前述两项信息,而后者打印一条消息,
指出餐馆正在营业。
代码:
class Restaurant():
def __init__(self, restaurant_name, cuisine_type):
self.name = restaurant_name
self.type = cuisine_type
def describe_restaurant(self):
print('Restaurant name: ' + self.name)
print('Cuisine type: ' + self.type)
def open_restaurant(self):
print(self.name + ' is opening.')
restaurant = Restaurant('MCdownald', 'fast food')
print(restaurant.name)
print(restaurant.type)
restaurant.describe_restaurant()
restaurant.open_restaurant()
结果:
例题9-4
描述:在为完成练习9-1而编写的程序中,
添加一个名为number_served 的属性,
并将其默认值设置为0。
根据这个类创建一个名为restaurant 的实例;
打印有多少人在这家餐馆就餐过,
然后修改这个值并再次打印它。
添加一个名为set_number_served() 的方法,
它让你能够设置就餐人数。
调用这个方法并向它传递一个值,
然后再次打印这个值。
添加一个名为increment_number_served() 的方法,
它让你能够将就餐人数递增。
调用这个方法并向它传递一个这样的值:
你认为这家餐馆每天可能接待的就餐人数。
代码:
class Restaurant():
def __init__(self, restaurant_name, cuisine_type):
self.restaurant_name = restaurant_name
self.cuisine_type = cuisine_type
self.number_served = 0
def set_number_served(self, people):
self.number_served = people
def increment_number_served(self, increment):
self.number_served += increment
def read_number_served(self):
print('The restaurant has served ' + str(self.number_served) + ' people.')
def describe_restaurant(self):
print('Restaurant name: ' + self.restaurant_name)
print('Cuisine type: ' + self.cuisine_type)
def open_restaurant(self):
print(self.restaurant_name + ' is opening.')
restaurant = Restaurant('MCdownald', 'fast food')
print(restaurant.restaurant_name)
print(restaurant.cuisine_type)
restaurant.describe_restaurant()
restaurant.open_restaurant()
restaurant.read_number_served()
restaurant.set_number_served(10)
restaurant.read_number_served()
restaurant.increment_number_served(10)
restaurant.read_number_served()
结果:
例题9-6
描述:冰淇淋小店是一种特殊的餐馆。
编写一个名为IceCreamStand 的类,
让它继承你为完成练习9-1或练习9-4而编写的Restaurant 类。
这两个版本的Restaurant 类都可以,
挑选你更喜欢的那个即可。
添加一个名为flavors 的属性,
用于存储一个由各种口味的冰淇淋组成的列表。
编写一个显示这些冰淇淋的方法。
创建一个IceCreamStand 实例,并调用这个方法。
代码:
class Restaurant():
def __init__(self, restaurant_name, cuisine_type):
self.restaurant_name = restaurant_name
self.cuisine_type = cuisine_type
self.number_served = 0
def set_number_served(self, people):
self.number_served = people
def increment_number_served(self, increment):
self.number_served += increment
def read_number_served(self):
print('The restaurant has served ' + str(self.number_served) + ' people.')
def describe_restaurant(self):
print('Restaurant name: ' + self.restaurant_name)
print('Cuisine type: ' + self.cuisine_type)
def open_restaurant(self):
print(self.restaurant_name + ' is opening.')
class IceCreamStand(Restaurant):
def __init__(self, restaurant_name, cuisine_type, flavors):
super().__init__(restaurant_name, cuisine_type)
self.flavors = flavors
def read_flavors(self):
print('We have the following flavors: ')
for flavor in self.flavors:
print(flavor)
flavors = ['Vanilla', 'Mango', 'Strawberry']
ice_restaurant = IceCreamStand('Haagen-Dazs', 'ice cream restaurant', flavors[:])
print(ice_restaurant.restaurant_name)
print(ice_restaurant.cuisine_type)
ice_restaurant.describe_restaurant()
ice_restaurant.open_restaurant()
ice_restaurant.read_number_served()
ice_restaurant.set_number_served(10)
ice_restaurant.read_number_served()
ice_restaurant.increment_number_served(10)
ice_restaurant.read_number_served()
ice_restaurant.read_flavors()
结果:
发现的问题:
- init()名称固定 两边是两个下划线
- Def
- 必须要有self这个参数
- 实例:restaurant = Restaurant()
- 可以在类外改变类的变量
- Super()不用传self