Beautiful Soup Prettify(formatter = 'xml') 已弃用？答案

【问题标题】：Beautiful Soup Prettify(formatter = 'xml') is deprecated?Beautiful Soup Prettify(formatter = 'xml') 已弃用？
【发布时间】：2020-04-05 05:53:43
【问题描述】：

当我尝试使用“xml”作为prettify() 格式的键时，出现错误。

这是我的代码，我试图将其解析为“xml”。但是当我尝试使用“html”作为键时，它可以正常工作。事实上，以 'minimal' 作为键，它工作得很好。

from bs4 import BeautifulSoup

doc = """
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title"><b>The Dormouse's story</b></p>

<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>

<p class="story">...</p>

"""
soupy = BeautifulSoup(doc, 'html.parser')
soupy.body.b.prettify(formatter='xml')

输出：我已经通过 element.py 并因此到达 Formatter.py(class Formatter) 但仍然无法解决它！

KeyError                                  Traceback(most recent call last)
<ipython-input-22-27d5e242bc68 > in < module >
--- -> 1 soupy.body.b.prettify(formatter='xml')

~/anaconda3/lib/python3.7/site-packages/bs4/element.py in prettify(self, encoding, formatter)
    1575         """
    1576         if encoding is None:
-> 1577             return self.decode(True, formatter=formatter)
    1578         else:
    1579             return self.encode(encoding, True, formatter=formatter)

~/anaconda3/lib/python3.7/site-packages/bs4/element.py in decode(self, indent_level, eventual_encoding, formatter)
    1472         # over again.
    1473         if not isinstance(formatter, Formatter):
-> 1474             formatter = self.formatter_for_name(formatter)
    1475         attributes = formatter.attributes(self)
    1476         attrs = []

~/anaconda3/lib/python3.7/site-packages/bs4/element.py in formatter_for_name(self, formatter)
    195         if isinstance(formatter, Callable):
    196             return c(entity_substitution=formatter)
--> 197         return c.REGISTRY[formatter]
    198 
    199     @property

KeyError: 'xml'

提前谢谢，我只是想知道为什么会这样？

【问题讨论】：

标签： html xml web-scraping beautifulsoup

【解决方案1】：

要将网站解析为xml，请使用 lxml 库。
安装：

pip install lxml

现在导入并使用它：

import lxml
...
#either
BeautifulSoup(doc, "lxml-xml") 
#or
BeautifulSoup(doc, "xml")

它显示key error，因为xml 不在他们的REGISTRY 中：

HTMLFormatter.REGISTRY['html'] = HTMLFormatter(
    entity_substitution=EntitySubstitution.substitute_html
)
HTMLFormatter.REGISTRY["html5"] = HTMLFormatter(
    entity_substitution=EntitySubstitution.substitute_html,
    void_element_close_prefix = None
)
HTMLFormatter.REGISTRY["minimal"] = HTMLFormatter(
    entity_substitution=EntitySubstitution.substitute_xml
)
HTMLFormatter.REGISTRY[None] = HTMLFormatter(
    entity_substitution=None
)
XMLFormatter.REGISTRY["html"] =  XMLFormatter(
    entity_substitution=EntitySubstitution.substitute_html
)
XMLFormatter.REGISTRY["minimal"] = XMLFormatter(
    entity_substitution=EntitySubstitution.substitute_xml
)
XMLFormatter.REGISTRY[None] = Formatter(
    Formatter(Formatter.XML, entity_substitution=None)
)

【讨论】：