作为列表成员的对象实例 --> 这是“pythonic”吗？这是乐理吗？ [关闭]

Question

我想听听您对此代码的意见或建议：

#!/usr/bin/env python3
# -*- coding: utf-8 -*-


# Defines the class (Element) that will be used in the Container
class Element:
    def __init__(self, address):
        # The address is the identifier for this element
        self._address = int(address)

    def theaddress(self):
        # Getter for the address
        return self._address

    def __eq__(self, other):
        # This function will be called if we like to check if this instanse is already a
        # member of the container instance
        print("A __eq__ called: %r == %r ?" % (self, other))
        return self._address == other._address


# Defines the class (Container) which holds n instances of Element class
class Container:
    def __init__(self):
        # Basically it is a list
        self._listcontainers = list()

    # If we like to append a new element instance, we have to check if new one is already available
    # with the same address. So we like to never had the same address twice or more times!
    def appendcontainer(self, possibleElement: Element = Element(1)):
        # Calls the __eq__ element of the Element class to check if this one (with exactly this address) is already present
        if possibleElement in self._listcontainers:
            # If the possibleElement is in the container list
            print('Address %i of this element %s is already existing.' % (possibleElement.theaddress(), possibleElement))
            return False
        else:
            # If possobleElement is new append it to the containerlist
            self._listcontainers.append(possibleElement)
            print('Added element: %s with address: %i' % (possibleElement, possibleElement.theaddress()))
            return True

    # Returns the available elements in the containers
    def lengthcontainers(self):
        return len(self._listcontainers)


def main():
    # List of containers
    myContainer = Container()

    # New element with address 1
    newElement1 = Element(1)
    myContainer.appendcontainer(newElement1)

    # New element with address 2
    newElement2 = Element(2)
    myContainer.appendcontainer(newElement2)

    # New element with address xyz
    newElement3 = Element(2) # You can play with the addresses...
    myContainer.appendcontainer(newElement3)

    print('Available elements: %i' % myContainer.lengthcontainers())


if __name__ == "__main__":
    main()

现在：

• 我有一个元素类，它代表一些数据的抽象。它本身也会包含一些逻辑作为私有方法......
• 我有一个包含 n 个元素实例的类（本例中为 Container）。
• 我需要防止添加具有相同属性的元素。在本例中 - 相同的地址。

问题：

• 我想知道这是否是识别元素的最先进技术？
• 也许有更好的方法在 Python 3 中执行此操作？
• 尤其是__eq__ 函数对我来说非常有趣。因为，_address 应该是一个私有变量，我在other._address 处收到警告-->“访问受保护的成员 _address of a class...”。我需要在这里考虑什么吗？

任何意见或建议都会对我很有帮助。实际上我只是在做原型设计，但它应该是在这种情况下保存一些数据的真实项目的基础。

Answer 1

我认为魔术方法（如__eq__、__le__ 等）是允许的（就代码风格而言）使用other 对象的受保护成员，所以我会忽略警告。

至于附加，如果可能的话，我建议使用set 而不是list。仅存储不同的元素是 set 的工作，您无需检查元素的存在，set 会为您完成。不要忘记为您的Element 类实现__hash__ 方法：

class Element:
    ...

    def __hash__(self):
        return hash(self._address)

    def __eq__(self, other):
        return self._address == other._address