用Python的`xml.etree.ElementTree.iterparse`拼接XML节

Question

我想使用xml.etree.ElementTree.iterparse()来抓取XML文件的某些部分。该文件有60 1B和1B行，因此我不想将其全部加载到内存中。我没有看到一种在xml库中输出整个XML子部分的方法。我认识到iterparse是迭代的，可能到目前为止还只是向前看。我该怎么做呢？

from xml.etree.ElementTree import iterparse

context = iterparse("file.xml", events=("start", "end"))

for event, elem in context:
    if event == 'start':
        if elem.tag == 'page':
            # Splice out this subset of the XML, including tags
            # Or, better, splice it if `<title>` includes "Foo".
    else:
        elem.clear()

XML大致如下所示：

<siteinfo>
    <page>
        <title>Foo</title>
            <text>Bar</text>
    </page>
    <page>
        <title>NotFoo</title>
        <text>NotBar</text>
    </page>
</siteinfo>

Answer 1

我尝试了一些东西，它并不是你所期望的输出，只是分享它是否对你有用

path='D:\data.xml'
from xml.etree import ElementTree as Et

context = Et.iterparse(path,events=("start", "end"))
root = None
for event, elem in context:
    if event=='end' or event=='start':
        if elem.text=='Foo':
            elem.clear()
root=elem
with open('d:\output.xml', 'wb') as file:
    Et.ElementTree(root).write(file, encoding='utf-8', xml_declaration=True)

输出文件：

<?xml version='1.0' encoding='utf-8'?>
<siteinfo>
    <page>
        **#some how this <title /> remains**
        ***<title />***
        <text>Bar</text>
    </page>
    <page>
        <title>NotFoo</title>
        <text>NotBar</text>
    </page>
</siteinfo>