如何在python中继承ElementTree.Element类？ [英] How to inherit ElementTree.Element class in python?

问题描述

我尝试定义一个继承ElementTree.Element的NewElement类。目标是添加更多方法，例如foo1（），foo2（）。

I try to define a NewElement class, which inherit ElementTree.Element. The goal is adding a few more methods, e.g. foo1(), foo2(), to it.

定义NewElement类：
将xml.etree.ElementTree导入为ET

Define NewElement class: import xml.etree.ElementTree as ET

class NewElement(ET.Element):
    def __init__(self):
        # Q1: how to init ET.Element? refer to ET's refer guide - http://docs.python.org/2/library/xml.etree.elementtree.html#xml.etree.ElementTree.SubElement
        pass
    def foo1(self):
        # do something on Element
        return self
    def foo2(self):
        # do something else on Element
        return self

要以这种方式使用NewElement：

a_element = ET.fromstring(xmlstring)    # Q2: how to generate a NewElement object instead of ET.Element one
a_element.foo1().foo2()     # this is my goal to easier use foo1, foo2 functions

问题是

第一季度-如何初始化NewElement的父节点？ ET的参考指南saide ET.Element可以初始化，但似乎只有元素本身没有孩子。

Q1 - how to init NewElement's parent? the ET's reference guide saide ET.Element can be initialized but it seems only the element itself without children.

第二季度-其他ET的类/功能返回Element，但是我希望是NewElement。我是否需要全部更改？

Q2 - other ET's class/function returns Element, but I expect NewElement. Do I need change all of them?

我是否在正确的方向上实现目标？还是改用多重继承？还是使用mixin？怎么样？ ...

Do I on the right direction to reach my goal? Or use multiple inheritance instead? Or use mixin? How? ...

感谢您的宝贵意见。

推荐答案

没必要这样做。只需制作 foo1 foo2 模块级别函数即可，这些函数接受的实例元素并返回实例：

It's unnecessary to do so. Simply make foo1 foo2 module level functions which accept instances of Element and return the instances:

foo2(foo1(a_element))

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