python类的私有属性和公共属性说明

class Base:
    def __init__(self, value):
        self.__value = value
 
b = Base(5)
print(assert b.__value)
 
Traceback (most recent call last):
  File "/Users/yangjiajia/Desktop/project/python/algebra/test.py", line 19, in <module>
    print(b.__value)
AttributeError: 'Base' object has no attribute '__value'

class Parent:
    def __init__(self, value):
        self.__value = value 
 
class Child(Parent):
    def get_value(self):
        return self.__value
 
child = Child(4)
print(child.get_value())
 
Traceback (most recent call last):
  File "/Users/yangjiajia/Desktop/project/python/algebra/test.py", line 24, in <module>
    print(child.get_value())
  File "/Users/yangjiajia/Desktop/project/python/algebra/test.py", line 21, in get_value
    return self.__value
AttributeError: 'Child' object has no attribute '_Child__value'

class Parent:
    def __init__(self, value):
        self.__value = value 
 
class Child(Parent):
    def name(self):
        names = 'yang'
 
    def get_value(self):
        return self.__value
 
child = Child(4)
print(child.__dict__)
 
{'_Parent__value': 4}

class Parent:
    def __init__(self, value):
        self._value = value 
 
class Child(Parent):
    def get_value(self):
        return self._value
 
child = Child(4)
assert child._value == 4

class Dog(object):
    __slots__ = ('__name', 'kind', 'level')
    def __init__(self,name,kind,level):#构造函数，定义属性和初始方法
        self.__name=name
        self.kind=kind
        self.level=level#赋值
        print(f"This is a {self.kind} dog called {self.__name} with level {self.level}")
 
    def run(self):#定义类中的方法
        print(f"{self.__name} is now running!")
 
    def roll_over(self):
        print(f"{self.__name} is now rolling over!")
 
    def change_level(self):
        self.level+=1#修改类中属性的值
        print(f"The level of {self.__name} is now {self.level}")

from Zoo.Dog import Dog#导包
 
dog=Dog("Halo","Husty",3)#实例化
 
dog.run()
dog.roll_over()
dog.change_level()#调用方法

print(dog.__name)