我正在使用 lxml 3.1.0（使用 easy_install 安装），并看到奇怪的结果：
> from lxml.html.clean import clean_html
> clean_html("<html><body><h1>hi</h1></body></html>")
'<div><body><h1>hi</h1></body></div>'
html标签被替换为div.
根据http://lxml.de/lxmlhtml.html#cleaning-up-html的示例 html 也会发生同样的情况
是什么赋予了？我是否遇到了 lxml 的错误，或者与 libxml2 的版本不兼容，或者这是以某种方式预期的？
我认为您需要一个Cleaner单独的page_structure：
>>> from lxml.html.clean import Cleaner
>>> cleaner = Cleaner(page_structure=False)
>>> cleaner.clean_html("<html><body><h1>hi</h1></body></html>")
'<html><body><h1>hi</h1></body></html>'
如此处所述，默认情况下page_structure是True。我怀疑您提供的站点上的文档不正确或已过时。
编辑#1：可以在源代码的这个测试中找到另一个确认这是预期行为。已提交拉取请求以更正文档。
编辑#2：截至 2013 年 4 月 28 日，拉取请求已合并到主服务器中。
页面的结构部分，如<head>,<html>和，如果是默认值，则将其<title>删除。page_structure=True要改变这一点：
import lxml.html.clean as clean
content = '<html><body><h1>hi</h1></body></html>'
cleaner = clean.Cleaner(page_structure=False)
cleaned = cleaner.clean_html(content)
print(cleaned)
# <html><body><h1>hi</h1></body></html>
请参阅类的文档字符串clean.Cleaner：
In [105]: clean.Cleaner?
Type: type
String Form:<class 'lxml.html.clean.Cleaner'>
File: /usr/lib/python2.7/dist-packages/lxml/html/clean.py
Definition: clean.Cleaner(self, doc)
Docstring:
Instances cleans the document of each of the possible offending
elements. The cleaning is controlled by attributes; you can
override attributes in a subclass, or set them in the constructor.
``scripts``:
Removes any ``<script>`` tags.
``javascript``:
Removes any Javascript, like an ``onclick`` attribute.
``comments``:
Removes any comments.
``style``:
Removes any style tags or attributes.
``links``:
Removes any ``<link>`` tags
``meta``:
Removes any ``<meta>`` tags
``page_structure``:
Structural parts of a page: ``<head>``, ``<html>``, ``<title>``.
``processing_instructions``:
Removes any processing instructions.
``embedded``:
Removes any embedded objects (flash, iframes)
``frames``:
Removes any frame-related tags
``forms``:
Removes any form tags
``annoying_tags``:
Tags that aren't *wrong*, but are annoying. ``<blink>`` and ``<marquee>``
``remove_tags``:
A list of tags to remove.
``allow_tags``:
A list of tags to include (default include all).
``remove_unknown_tags``:
Remove any tags that aren't standard parts of HTML.
``safe_attrs_only``:
If true, only include 'safe' attributes (specifically the list
from `feedparser
<http://feedparser.org/docs/html-sanitization.html>`_).
``add_nofollow``:
If true, then any <a> tags will have ``rel="nofollow"`` added to them.
``host_whitelist``:
A list or set of hosts that you can use for embedded content
(for content like ``<object>``, ``<link rel="stylesheet">``, etc).
You can also implement/override the method
``allow_embedded_url(el, url)`` or ``allow_element(el)`` to
implement more complex rules for what can be embedded.
Anything that passes this test will be shown, regardless of
the value of (for instance) ``embedded``.
Note that this parameter might not work as intended if you do not
make the links absolute before doing the cleaning.
``whitelist_tags``:
A set of tags that can be included with ``host_whitelist``.
The default is ``iframe`` and ``embed``; you may wish to
include other tags like ``script``, or you may want to
implement ``allow_embedded_url`` for more control. Set to None to
include all tags.
This modifies the document *in place*.
Constructor information:
Definition:clean.Cleaner(self, **kw)