0
python第九节：类的使用（3）
source link: https://blog.51cto.com/u_16427934/9976312
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.
类的继承：
一个类继承另一个类时，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。
创建子类时，必须在括号内指定父类的名称。子类和父类可以不再同一个py文件中。
继承关系中，父类的__init__方法不会被自动调用，如果需要，必须在子类中明确调用它。
在test20240117.py文件中：
class Dog():
pet_shop = '萌宠小屋'
def __init__(self, name, age):
self.name = name
self.age = age
# 坐
def sit(self):
print(self.name.title() + " is now sitting.")
# 打滚
def roll_over(self):
print(self.name.title() + " rolled over!")
def _say_hi(self):
print("say hi!")在test20240307.py文件中：
import test20240117 as test
class Dog2(test.Dog):
def __init__(self):
pass
def sit(self):
print("子类sit")
dog2 = Dog2()
dog2.sit()"C:\Program Files\Python312\python.exe" D:/pythonProject/test/test20240307.py
子类sit
重写父类的方法
在子类中定义一个方法，和父类的方法同名，子类中的方法将覆盖父类中方法。
class Animal():
pet_shop = '萌宠小屋'
def __init__(self, name, age):
self.name = name
self.age = age
def say_hi(self):
print("say hi!")
class Dog(Animal):
pet_shop = '汪汪队'
def __init__(self, name, age):
self.name = name
self.age = age
# 坐
def sit(self):
print(self.name.title() + " is now sitting.")
# 打滚
def roll_over(self):
print(self.name.title() + " rolled over!")
def say_hi(self):
print("wang wang!")
animal = Animal('动物',2)
animal.say_hi()
dog = Dog('狗子',3)
dog.say_hi()say hi!
wang wang!
例子：多重继承，按照在在子类定义时，括号中的顺序继承，同名的优先继承排在前面的类中的方法。
class Animal():
pet_shop = '萌宠小屋'
def __init__(self, name, age):
self.name = name
self.age = age
def say_hi(self):
print("say hi!")
def say_ok(self):
print("animal say ok!")
class livestock():
def __init__(self, name, age):
self.name = name
self.age = age
def say_hi(self):
print("家畜!")
def eat(self):
print('家畜吃饭！')
def say_ok(self):
print("livestock say ok!")
class Dog(Animal,livestock):
pet_shop = '汪汪队'
def __init__(self, name, age):
self.name = name
self.age = age
# 坐
def sit(self):
print(self.name.title() + " is now sitting.")
# 打滚
def roll_over(self):
print(self.name.title() + " rolled over!")
def say_hi(self):
print("wang wang!")
animal = Animal('动物',2)
animal.say_hi()
dog = Dog('狗子',3)
dog.say_hi()
dog.eat()
dog.say_ok()say hi!
wang wang!
家畜吃饭！
animal say ok!
在子类中调用父类的方法，使用super()关键字。
class Animal():
pet_shop = '萌宠小屋'
def __init__(self, name, age):
self.name = name
self.age = age
def say_hi(self):
print("Animal say hi!")
def say_ok(self):
print("animal say ok!")
class Dog(Animal):
pet_shop = '汪汪队'
def __init__(self, name, age,sex):
super().__init__(name, age)
# 坐
def sit(self):
super().say_hi()
print(self.name.title() + " is now sitting.")
# 打滚
def roll_over(self):
print(self.name.title() + " rolled over!")
def say_hi(self):
print("wang wang!")
dog = Dog('旺财',5,'female')
dog.sit()Animal say hi!
Recommend
About Joyk
Aggregate valuable and interesting links.
Joyk means Joy of geeK