python-类

 1 class Dog():  #定义Dog类,python中首字母大写的名称指的是类
 2     """A simple attempt to model a dog."""
 3     
 4     def __init__(self, name, age):        #类中的函数称为方法。_init_()是一种特殊方法，每当根据Dog类创建新实例，python会自动运行它。
#开头和末尾的上下划线，是一种约定，旨在避免python默认方法和普通方法发生冲突。
 5         """Initialize name and age attributes."""
 6         self.name = name
 7         self.age = age
 8         
 9     def sit(self):
10         """Simulate a dog sitting in response to a command."""
11         print(self.name.title() + " is now sitting.")
12 
13     def roll_over(self):
14         """Simulate rolling over in response to a command."""
15         print(self.name.title() + " rolled over!")
16         
17 
18 my_dog = Dog(‘willie‘, 6)
19 your_dog = Dog(‘lucy‘, 3)
20 
21 print("My dog‘s name is " + my_dog.name.title() + ".")
22 print("My dog is " + str(my_dog.age) + " years old.")
23 my_dog.sit()
24 
25 print("\nMy dog‘s name is " + your_dog.name.title() + ".")
26 print("My dog is " + str(your_dog.age) + " years old.")
27 your_dog.sit()