如何使用 lxml 选择和更新混合内容中的文本节点？

Question

我需要检查 XML 文件中所有text()节点中的所有单词。 我正在使用 XPath //text()来选择文本节点和一个正则表达式来选择单词。 如果该词存在于一组关键字中，我需要将其替换为某些内容并更新 XML。

通常使用.text设置元素的文本，但 _Element 上的.text只会更改第一个子文本节点。 在混合内容元素中，其他文本节点实际上是其前一个兄弟节点的.tail 。

如何更新所有文本节点？

在下面的简化示例中，我只是想将匹配的关键字括在方括号中...

输入 XML

<doc>
    <para>I think the only card she has <gotcha>is the</gotcha> Lorem card. We have so many things that we have to do
        better... and certainly ipsum is one of them. When other <gotcha>websites</gotcha> give you text, they're not
        sending the best. They're not sending you, they're <gotcha>sending words</gotcha> that have lots of problems
        and they're <gotcha>bringing</gotcha> those problems with us. They're bringing mistakes. They're bringing
        misspellings. They're typists… And some, <gotcha>I assume</gotcha>, are good words.</para>
</doc>

期望输出

<doc>
    <para>I think [the] only card she has <gotcha>[is] [the]</gotcha> Lorem card. We have so many things that we have to do
        better... and certainly [ipsum] [is] one of them. When other <gotcha>websites</gotcha> give you text, they're not
        sending [the] [best]. They're not sending you, they're <gotcha>sending words</gotcha> that have lots of [problems]
        and they're <gotcha>bringing</gotcha> those [problems] with us. They're bringing [mistakes]. They're bringing
        misspellings. They're typists… And some, <gotcha>I assume</gotcha>, are good words.</para>
</doc>

Answer 1

我在文档中找到了这个解决方案的关键： Using XPath to find text

具体地， is_text和is_tail的性质_ElementUnicodeResult 。

使用这些属性，我可以判断是否需要更新父_Element的.text或.tail属性。

起初这有点难以理解，因为当您在文本节点（ _ElementUnicodeResult getparent()上使用getparent() ，它是其前一个兄弟节点（ .is_tail == True ）的尾部，前一个兄弟.is_tail == True是作为父节点返回的； 不是真正的父母。

例子...

Python

import re
from lxml import etree

xml = """<doc>
    <para>I think the only card she has <gotcha>is the</gotcha> Lorem card. We have so many things that we have to do
        better... and certainly ipsum is one of them. When other <gotcha>websites</gotcha> give you text, they're not
        sending the best. They're not sending you, they're <gotcha>sending words</gotcha> that have lots of problems
        and they're <gotcha>bringing</gotcha> those problems with us. They're bringing mistakes. They're bringing
        misspellings. They're typists… And some, <gotcha>I assume</gotcha>, are good words.</para>
</doc>
"""


def update_text(match, word_list):
    if match in word_list:
        return f"[{match}]"
    else:
        return match


root = etree.fromstring(xml)

keywords = {"ipsum", "is", "the", "best", "problems", "mistakes"}

for text in root.xpath("//text()"):
    parent = text.getparent()
    updated_text = re.sub(r"[\w]+", lambda match: update_text(match.group(), keywords), text)
    if text.is_text:
        parent.text = updated_text
    elif text.is_tail:
        parent.tail = updated_text

etree.dump(root)

输出（转储到控制台）

<doc>
    <para>I think [the] only card she has <gotcha>[is] [the]</gotcha> Lorem card. We have so many things that we have to do
        better... and certainly [ipsum] [is] one of them. When other <gotcha>websites</gotcha> give you text, they're not
        sending [the] [best]. They're not sending you, they're <gotcha>sending words</gotcha> that have lots of [problems]
        and they're <gotcha>bringing</gotcha> those [problems] with us. They're bringing [mistakes]. They're bringing
        misspellings. They're typists… And some, <gotcha>I assume</gotcha>, are good words.</para>
</doc>