python - 如何从Python中的单个类继承一个类的多个实例

Question

免责声明:我是编程新手，刚刚开始学习类和继承，所以也许是我缺乏理解导致了我的问题？

我在单独的文件 person.py 和 address.py 中创建了两个类。

人员类继承自地址类，但是一个人可以有多个地址(邮政地址、实际地址等)。我如何为每种类型继承地址类的多个实例。

我的目标是最终为 future 的项目建立一个公共(public)类库，因此非常感谢有关此概念的任何帮助或建设性意见。

我希望能够创建类似下面的代码，其中邮政地址和物理地址都使用 Address 类:

employee = Person()
employee.set_postal_address("342 Gravelpit Terrace","Bedrock")
employee.set_physical_address("742 Evergreen Tce", "Springfield")

下面是我的代码，我没有在 Person() 类中创建对 Address() 的任何引用，因为我不确定如何实现这一点？

# address.py

class Address:
    def __init__(self):
        self.__line1 = None
        self.__line2 = None
        self.__town_city = None
        self.__post_code = None
        self.__state_region = None
        self.__country = None

    # Line 1
    def get_line1(self):
        return self.__line1

    def set_line1(self, line1):
        self.__line1 = line1

    #etc....

# person.py

from address import * 

class Person(Address):

    def __init__(self):
        self.__first_name = None
        self.__last_name = None
        self.__postal_address = []
        self.__physical_adress = []


    def set_postal_address(self):
        # use the address class 
        # return a list of address values
        self.__postal_address = []

    def set_physical_address(self):
        # use the address class 
        # return a list of address values
        self.__physical_address = []  

    #etc...

非常感谢任何帮助。如果有更好的方法来处理这个问题请告诉我。

Answer 1

创建Person类时，您不一定需要继承Address。实现目标的一种方法是在 Person 类中初始化一个 Address 类对象。

# address.py

class Address:
    def __init__(self, **kwargs):
        self.__line1 = kwargs.get('__line1')
        self.__line2 = kwargs.get('__line2')
        self.__town_city = kwargs.get('__town_city')
        self.__post_code = kwargs.get('__post_code')
        self.__state_region = kwargs.get('__state_region')
        self.__country = kwargs.get('__country')

    # Line 1
    def get_line1(self):
        return self.__line1

    def set_line1(self, line1):
        self.__line1 = line1

    #etc....

# person.py

from address import * 

class Person:

    def __init__(self, **kwargs):
        self.__first_name = kwargs.get('__first_name')
        self.__last_name = kwargs.get('__last_name')
        self.__postal_address = None
        self.__physical_address = None


    def set_postal_address(self, **kwargs):
        # use the address class 
        self.__postal_address = Address(**kwargs)

    def set_physical_address(self, **kwargs):
        # use the address class 
        self.__physical_address = Address(**kwargs)

    #etc...

这允许您防止继承的方法在给定的类对象中变得困惑，但仍然允许您保持良好的类结构。

然后你可以这样做:

bob=Person(__first_name='Bob', __last_name='Smith')
bob.set_postal_address(__line1='42 Wallaby Way', __town_city='Sydney')
# Since we are using kwargs.get() any not specified Kwarg comes out as None.
# Now `__postal_address` is its own Address class and comes with Address methods
bob.__postal_address.set__line2('Apt 3B')

现在有时您希望从更高级别的类继承通用方法。您可以在此处阅读有关 python 类的更多信息:( https://docs.python.org/3.6/tutorial/classes.html )