良好的python XML解析器，可处理名称空间繁重的文档 [英] Good python XML parser to work with namespace heavy documents

问题描述

Python elementTree似乎无法用于名称空间.我有什么选择? BeautifulSoup也是带有名称空间的垃圾. 我不想剥掉它们.

Python elementTree seems unusable with namespaces. What are my alternatives? BeautifulSoup is pretty rubbish with namespaces too. I don't want to strip them out.

特定python库如何获取命名空间元素及其集合的示例全为+1.

Examples of how a particular python library gets namespaced elements and their collections are all +1.

编辑:您能否使用您选择的库来提供用于处理此现实世界用例的代码?

Could you provide code to deal with this real world use-case using your library of choice?

您将如何获取字符串'Line Break'，'2.6'和列表['PYTHON'，'XML'，'XML-NAMESPACES']

<?xml version="1.0" encoding="UTF-8"?>
<zs:searchRetrieveResponse
    xmlns="http://unilexicon.com/vocabularies/"
    xmlns:zs="http://www.loc.gov/zing/srw/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:lom="http://ltsc.ieee.org/xsd/LOM">
    <zs:records>
        <zs:record>
            <zs:recordData>
                <srw_dc:dc xmlns:srw_dc="info:srw/schema/1/dc-schema">
                    <name>Line Break</name>
                    <dc:title>Processing XML namespaces using Python</dc:title>
                    <dc:description>How to get contents string from an element,
                        how to get a collection in a list...</dc:description>
                    <lom:metaMetadata>
                        <lom:identifier>
                            <lom:catalog>Python</lom:catalog>
                            <lom:entry>2.6</lom:entry>
                        </lom:identifier>
                    </lom:metaMetadata>
                    <lom:classification>
                        <lom:taxonPath>
                            <lom:taxon>
                                <lom:id>PYTHON</lom:id>
                            </lom:taxon>
                        </lom:taxonPath>
                    </lom:classification>
                    <lom:classification>
                        <lom:taxonPath>
                            <lom:taxon>
                                <lom:id>XML</lom:id>
                            </lom:taxon>
                        </lom:taxonPath>
                    </lom:classification>
                    <lom:classification>
                        <lom:taxonPath>
                            <lom:taxon>
                                <lom:id>XML-NAMESPACES</lom:id>
                            </lom:taxon>
                        </lom:taxonPath>
                    </lom:classification>
                </srw_dc:dc>
            </zs:recordData>
        </zs:record>
        <!-- ... more records ... -->
    </zs:records>
</zs:searchRetrieveResponse>

推荐答案

lxml 具有名称空间感知功能.

lxml is namespace-aware.

>>> from lxml import etree
>>> et = etree.XML("""<root xmlns="foo" xmlns:stuff="bar"><bar><stuff:baz /></bar></root>""")
>>> etree.tostring(et, encoding=str) # encoding=str only needed in Python 3, to avoid getting bytes
'<root xmlns="foo" xmlns:stuff="bar"><bar><stuff:baz/></bar></root>'
>>> et.xpath("f:bar", namespaces={"b":"bar", "f": "foo"})
[<Element {foo}bar at ...>]

在您的示例中:

from lxml import etree

# remove the b prefix in Python 2
# needed in python 3 because
# "Unicode strings with encoding declaration are not supported."
et = etree.XML(b"""...""")

ns = {
    'lom': 'http://ltsc.ieee.org/xsd/LOM',
    'zs': 'http://www.loc.gov/zing/srw/',
    'dc': 'http://purl.org/dc/elements/1.1/',
    'voc': 'http://www.schooletc.co.uk/vocabularies/',
    'srw_dc': 'info:srw/schema/1/dc-schema'
}

# according to docs, .xpath returns always lists when querying for elements
# .find returns one element, but only supports a subset of XPath
record = et.xpath("zs:records/zs:record", namespaces=ns)[0]
# in this example, we know there's only one record
# but else, you should apply the following to all elements the above returns

name = record.xpath("//voc:name", namespaces=ns)[0].text
print("name:", name)

lom_entry = record.xpath("zs:recordData/srw_dc:dc/"
                         "lom:metaMetadata/lom:identifier/"
                         "lom:entry",
                         namespaces=ns)[0].text

print('lom_entry:', lom_entry)

lom_ids = [id.text for id in
           record.xpath("zs:recordData/srw_dc:dc/"
                        "lom:classification/lom:taxonPath/"
                        "lom:taxon/lom:id",
                        namespaces=ns)]

print("lom_ids:", lom_ids)

输出:

name: Frank Malina
lom_entry: 2.6
lom_ids: ['PYTHON', 'XML', 'XML-NAMESPACES']

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