为什么getparent()不能按预期工作? [英] Why getparent() don't work as expected?

问题描述

我需要对其中一个标记内的文本进行一些操作，并希望为其找到的每个文本节点获取父标记

I need to make some manipulations with text inside one of tags and want to get parent tag for every found text node for it

代码:

import lxml.etree
import pprint
s = '''
<data>
    data text
    <foo>foo - <bar>bar</bar> text</foo>
    data text
    <bar>
        bar text
        <baz>baz text</baz>
        <baz>baz text</baz>
        bar text
    </bar>
    data text
</data>
'''
etree = lxml.etree.fromstring(s)
text = etree.xpath("//text()[normalize-space()]")
pprint.pprint([(s.getparent().tag, s.strip()) for s in text])

输出:

[('data', 'data text'),
 ('foo', 'foo -'),
 ('bar', 'bar'),
 ('bar', 'text'),
 ('foo', 'data text'),
 ('bar', 'bar text'),
 ('baz', 'baz text'),
 ('baz', 'baz text'),
 ('baz', 'bar text'),
 ('bar', 'data text')]

我期望:

[('data', 'data text'),
 ('foo', 'foo -'),
 ('bar', 'bar'),
 ('foo', 'text'),
 ('data', 'data text'),
 ('bar', 'bar text'),
 ('baz', 'baz text'),
 ('baz', 'baz text'),
 ('bar', 'bar text'),
 ('data', 'data text')]

我的错误在哪里?看起来像我输出中的标签-不是树中文本的父标签，而只是上一个标签.

Where is my mistake? Looks like tags in my output - is not parent tag for text in tree, but simply previous tag.

修改 我需要的工作代码:

Edit Working code for my needs:

etree = lxml.etree.fromstring(s)
text = etree.xpath("//text()[normalize-space()]")
for s in text:
    if s.is_tail:
        print(s.getparent().getparent().tag, s.strip())
    else:
        print(s.getparent().tag, s.strip())

推荐答案

您所看到的与 tail 属性(在结束标记之后的文本)，这是ElementTree和lxml表示XML的方式的独特之处.

What you are seeing has to do with the tail property (text immediately following an end tag), which is a peculiarity of the ElementTree and lxml way of representing XML.

通过添加 is_tail 测试(返回True如果文本是代码的尾部文本")，则可以看到正在发生的情况:

By adding a is_tail test (returns True if the text is "tail text") to your code, you can see what's happening:

import lxml.etree
import pprint

s = '''
<data>
    data text
    <foo>foo - <bar>bar</bar> text</foo>
    data text
    <bar>
        bar text
        <baz>baz text</baz>
        <baz>baz text</baz>
        bar text
    </bar>
    data text
</data>
'''

etree = lxml.etree.fromstring(s)
text = etree.xpath("//text()[normalize-space()]")
pprint.pprint([(s.getparent().tag, s.is_tail, s.strip()) for s in text])

输出:

[('data', False, 'data text'),
 ('foo', False, 'foo -'),
 ('bar', False, 'bar'),§
 ('bar', True, 'text'),
 ('foo', True, 'data text'),
 ('bar', False, 'bar text'),
 ('baz', False, 'baz text'),
 ('baz', False, 'baz text'),
 ('baz', True, 'bar text'),
 ('bar', True, 'data text')] 

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