面向对象-继承
经典类：不由任意内置类型派生出的类，称之为经典类
新式类：
python面向对象的继承指的是多个类之间的所属关系，即子类默认继承父类的所有属性和方法。
class A(object):
def __init__(self):
self.num = 1
def info_print(self):
print(self.num)
class B(A):
pass
res = B()
res.info_print()
在python中，所有类都默认继承object类，object类是顶级类或基类，其他子类称之为派生类。
① 单继承
class Master(object):
def __init__(self):
self.kongfu = "[古法煎饼果子配方]"
def make_cake(self):
print(f"运用{self.kongfu}制作煎饼果子")
class Tudi(Master):
pass
xiaoding = Tudi()
print(xiaoding.kongfu)
xiaoding.make_cake()
② 多继承
class Master(object):
def __init__(self):
self.kongfu = "[古法煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(object):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f"运用{self.kongfu}制作煎饼果子")
class Tudi(School,Master):
pass
xiaoding = Tudi()
print(xiaoding.kongfu)
xiaoding.make_cake()
当一个类有多个父类时，默认使用第一个父类的同名属性和方法。
3.子类重写父类同名方法和属性
class Master(object):
def __init__(self):
self.kongfu = "[古法煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(object):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f"运用{self.kongfu}制作煎饼果子")
class Tudi(School,Master):
def __init__(self):
self.kongfu = "[独创煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
xiaoding = Tudi()
print(xiaoding.kongfu)
xiaoding.make_cake()
4.子类调用父类的同名方法和属性
class Master(object):
def __init__(self):
self.kongfu = "[古法煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(object):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f"运用{self.kongfu}制作煎饼果子")
class Tudi(School,Master):
def __init__(self):
self.kongfu = "[独创煎饼果子配方]"
def make_cake(self):
self.__init__()
print(f'运用{self.kongfu}制作煎饼果子')
def make_master_cake(self):
Master.__init__(self)
Master.make_cake(self)
def make_school_cake(self):
School.__init__(self)
School.make_cake(self)
xiaoding = Tudi()
xiaoding.make_cake()
xiaoding.make_master_cake()
xiaoding.make_school_cake()
5.多层继承
class Master(object):
def __init__(self):
self.kongfu = "[古法煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(object):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f"运用{self.kongfu}制作煎饼果子")
class Tudi(School,Master):
def __init__(self):
self.kongfu = "[独创煎饼果子配方]"
def make_cake(self):
self.__init__()
print(f'运用{self.kongfu}制作煎饼果子')
def make_master_cake(self):
Master.__init__(self)
Master.make_cake(self)
def make_school_cake(self):
School.__init__(self)
School.make_cake(self)
class Tusun(Tudi):
pass
xiaowang = Tusun()
print(xiaowang.kongfu)
xiaowang.make_cake()
6.super()调用父类方法
class Master(object):
def __init__(self):
self.kongfu = "[古法煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(Master):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f"运用{self.kongfu}制作煎饼果子")
super().__init__()
super(School, self).make_cake()
class Tudi(School):
def __init__(self):
self.kongfu = "[独创煎饼果子配方]"
def make_cake(self):
self.__init__()
print(f'运用{self.kongfu}制作煎饼果子')
def make_master_cake(self):
Master.__init__(self)
Master.make_cake(self)
def make_school_cake(self):
School.__init__(self)
School.make_cake(self)
def make_old_cake(self):
super().__init__()
super(Tudi, self).make_cake()
xiaoding = Tudi()
xiaoding.make_old_cake()
使用super()可以自动查找父类，调用顺序遵循__mro__类属性的属性。
（什么是mro类属性）
【适合单继承情况使用】
在多继承的情况下：
每个类开始调用根据mro顺序逐个开始，然后逐个进行结束
7.私有权限
① 定义私有属性和方法（设置某个实例属性或实例方法不继承给子类）
设置私有权限的方法，在属性名和方法名前面加上两个下划线
class Master(object):
def __init__(self):
self.kongfu = "[传统煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(object):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class Tudi(School,Master):
def __init__(self):
self.kongfu = "[独创煎饼果子配方]"
self.__money = 200
def __info_print(self):
print(self.kongfu)
print(self.__money)
def make_cake(self):
self.__init__()
print(f'运用{self.kongfu}制作煎饼果子')
def make_master_cake(self):
Master.__init__(self)
Master.make_cake(self)
def make_school_cake(self):
School.__init__(self)
School.make_cake(self)
class Tusun(Tudi):
pass
xiaoding = Tudi()
print(xiaoding.__money)
xiaoding.__info_print()
xiaowang = Tusun()
print(xiaowang.__money)
xiaowang.__info_print()
私有属性和私有方法只能在类中访问和修改
② 获取和修改私有属性值
在python中，一般定义函数名get_xx用来获取私有属性值，定义set_xx用来修改私有属性值
class Master(object):
def __init__(self):
self.kongfu = "[传统煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class School(object):
def __init__(self):
self.kongfu = "[现代煎饼果子配方]"
def make_cake(self):
print(f'运用{self.kongfu}制作煎饼果子')
class Tudi(School,Master):
def __init__(self):
self.kongfu = "[独创煎饼果子配方]"
self.__money = 200
def get_money(self):
return self.__money
def set_money(self):
self.__money = 50
def __info_print(self):
print(self.kongfu)
print(self.__money)
def make_cake(self):
self.__init__()
print(f'运用{self.kongfu}制作煎饼果子')
def make_master_cake(self):
Master.__init__(self)
Master.make_cake(self)
def make_school_cake(self):
School.__init__(self)
School.make_cake(self)
class Tusun(Tudi):
pass
xiaoding = Tudi()
print(xiaoding.get_money())
xiaoding.set_money()
print(xiaoding.get_money())
Original: https://blog.csdn.net/weixin_44226181/article/details/121266367
Author: Ding Jiaxiong
Title: python面向对象-2 继承
原创文章受到原创版权保护。转载请注明出处：https://www.johngo689.com/783058/
转载文章受原作者版权保护。转载请注明原作者出处！