创建类
#!/usr/bin/env python # --*-- encoding:utf-8 --*-- class Dog(): """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): """模拟小狗别命令时蹲下""" print(self.name.title() + " is now sitting.") def roll_over(self): """模拟小狗被命中时打滚""" print(self.name.title() + " rolled over!") my_dog = Dog('willie',6) your_dog = Dog('lucy',3) # print("My dog's name is " + my_dog.name.title() + ".") # print("My dog is " + str(my_dog.age) + " years old.") my_dog.sit() print("\nYour dog's name is " + your_dog.name.title() + ".") print("Your dog is " + str(your_dog.age) + " years old.") your_dog.sit() 给属性指定默认值 #!/usr/bin/env python # --*-- encoding:utf-8 --*-- class Car(): def __init__(self,make,model,year): """模拟汽车的的属性""" self.make = make self.model = model self.year = year self.odometer_reading = 0 def get_descriptive_name(self): """返回整洁的描述性信息""" long_name = str(self.year) + ' ' + self.make + ' ' + self.model return long_name.title() def read_odometer(self): """打印一条指出汽车里程的消息""" print("This car has " + str(self.odometer_reading) + " miles on it.") my_new_car = Car('audi','a3',2016) print(my_new_car.get_descriptive_name()) my_new_car.read_odometer() 修改属性的值： 1：直接修改属性的值 
#!/usr/bin/env python# --*-- encoding:utf-8 --*--class Car(): def __init__(self,make,model,year): """模拟汽车的的属性""" self.make = make self.model = model self.year = year self.odometer_reading = 0 def get_descriptive_name(self): """返回整洁的描述性信息""" long_name = str(self.year) + ' ' + self.make + ' ' + self.model return long_name.title() def read_odometer(self): """打印一条指出汽车里程的消息""" print("This car has " + str(self.odometer_reading) + " miles on it.")my_new_car = Car('audi','a3',2016)print(my_new_car.get_descriptive_name())my_new_car.odometer_reading = 23my_new_car.read_odometer() 2：通过方法修改属性的值
#!/usr/bin/env python# --*-- encoding:utf-8 --*--class Car(): def __init__(self,make,model,year): """模拟汽车的的属性""" self.make = make self.model = model self.year = year self.odometer_reading = 0 def get_descriptive_name(self): """返回整洁的描述性信息""" long_name = str(self.year) + ' ' + self.make + ' ' + self.model return long_name.title() def read_odometer(self): """打印一条指出汽车里程的消息""" print("This car has " + str(self.odometer_reading) + " miles on it.") def update_odometer(self,mileage): """将里程表读书设置为指定的值""" self.odometer_reading = mileagemy_new_car = Car('audi','a3',2016)print(my_new_car.get_descriptive_name())my_new_car.update_odometer(23)my_new_car.read_odometer() #!/usr/bin/env python# --*-- encoding:utf-8 --*--class Car(): def __init__(self,make,model,year): """模拟汽车的的属性""" self.make = make self.model = model self.year = year self.odometer_reading = 25 def get_descriptive_name(self): """返回整洁的描述性信息""" long_name = str(self.year) + ' ' + self.make + ' ' + self.model return long_name.title() def read_odometer(self): """打印一条指出汽车里程的消息""" print("This car has " + str(self.odometer_reading) + " miles on it.") def update_odometer(self,mileage): """将里程表读数设置为指定的值 禁止将里程表读数往回调""" if mileage >= self.odometer_reading: self.odometer_reading = mileage else: print("You can't roll back an odometer!")my_new_car = Car('audi','a3',2016)print(my_new_car.get_descriptive_name())my_new_car.update_odometer(23)my_new_car.read_odometer()执行结果：2016 Audi A3You can't roll back an odometer!This car has 25 miles on it. 3：通过方法对属性的值进行递增
继承
如果编写的类是另一个现成类的特殊版本，可使用继承。一个类集成另一个类时，它将自动获得另一个类的所有属性和方法；原有的类称为父类，而新类称为子类。
子类继承了其父类的所有属性和方法，同时还可以定义自己的属性和方法。