在lxml中使用cssselect的XHTML命名空间问题 [英] XHTML namespace issues with cssselect in lxml
问题描述
我有问题使用cssselect与XHTML（或XML与命名空间）。虽然文档说如何在csselect中使用命名空间我不明白它： cssselect命名空间
I have problems using cssselect with a XHTML (or XML with namespace). Although the documentation says how to use namespace in csselect I do not understand it: cssselect namespaces
我的输入XHTML字符串：
My Input XHTML string:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Teststylesheet</title>
<style type="text/css">
/*<![CDATA[*/
ol{margin:0;padding:0}
/*]]>*/
</style>
</head>
<body>
</body>
</html>
我的Python脚本：
My Python Script:
parser = etree.XMLParser()
tree = etree.fromstring(xhtmlstring, parser).getroottree()
for style in CSSSelector("style")(tree):
print "HAVE CSS!"
python脚本不打印任何有CSS！。使用 etree.HTMLParser 而不是 etree.XMLParser 工作，但我真的想使用XMLParser并保留一切（命名空间，结构）的XHTML。
The python script does not print any Have CSS!. Using the etree.HTMLParser instead of etree.XMLParser works but I really want to use the XMLParser and keep everything (namespace, structure) of the XHTML.
任何人都可以帮我解决这个命名空间的问题吗？
Can anybody help me with this namespace problem?
推荐答案
cssselect.CSSSelector （版本2.0）显示如何使用命名空间：
The doc string for cssselect.CSSSelector (version 2.0) shows how to use namespaces:
class CSSSelector(etree.XPath):
""" ...
To use CSS namespaces, you need to pass a prefix-to-namespace
mapping as ``namespaces`` keyword argument::
>>> rdfns = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'
>>> select_ns = cssselect.CSSSelector('root > rdf|Description',
... namespaces={'rdf': rdfns})
>>> rdf = etree.XML((
... '<root xmlns:rdf="%s">'
... '<rdf:Description>blah</rdf:Description>'
... '</root>') % rdfns)
>>> [(el.tag, el.text) for el in select_ns(rdf)]
[('{http://www.w3.org/1999/02/22-rdf-syntax-ns#}Description', 'blah')]
"""
您的 cssselect.CSSSelector 版本没有命名空间参数，那么您的lxml版本可能需要升级。
If you've tried this but your version of cssselect.CSSSelector does not have a namespaces parameter, then your version of lxml may need to be upgraded.
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