python - 如何使用 Python 按条件查找和删除 XML 文件(带有 namespace )中的元素

Question

我有一个 XML 文件，我想根据条件从中删除元素。但是，XML 文件的命名空间由于某些不清楚的原因不允许我执行所描述的过程:1 , 2 , 3 , 4和 5 .

我的 XML 如下所示:

    <?xml version='1.0' encoding='UTF-8'?>
        <PcGts xmlns="http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15 http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15/pagecontent.xsd">
            <Page imageFilename="1.png">
                <TextRegion custom="a">
                    <TextLine custom="readingOrder {index:0;}" id="Ar0010001l1">
                        <TextEquiv>
                            <Unicode> abc </Unicode>
                        </TextEquiv>
                    </TextLine>
                    <TextLine custom="readingOrder {index:1;}" id="Ad0010100l2">
                        <TextEquiv>
                            <Unicode />
                        </TextEquiv>
                </TextRegion>
            </Page>
        </PcGts>

我的目标是清除所有 TextLine 的“Unicode”标记中没有文本的节点。所以输出将是:

    <?xml version='1.0' encoding='UTF-8'?>
        <PcGts xmlns="http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15 http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15/pagecontent.xsd">
            <Page imageFilename="1.png">
                <TextRegion custom="a">
                    <TextLine custom="readingOrder {index:0;}" id="Ar0010001l1">
                        <TextEquiv>
                            <Unicode> abc </Unicode>
                        </TextEquiv>
                    </TextLine>
                </TextRegion>
            </Page>
        </PcGts>

我尝试使用上面链接中的一些建议。但是:

 import lxml.etree as ET
 data = ET.parse(file)
 root = data.getroot()
 for x in root.xpath("//Unicode"):
     print(x.text)

没有找到任何标签。再一次尝试:

for x in root.xpath("//{http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15}Unicode"):
   print(x.text)

抛出“XPathEvalError:无效表达式”

那么，从该 XML 文件中删除 Unicode 标记为空的所有节点的最简单方法是什么(以及如何找到它们？)？

谢谢。

Answer 1

首先，您的 xml 缺少 <TextLine custom="readingOrder {index:1;}" id="Ad0010100l2"> 的结束标记，但是如果您将其插入到适当的位置，则以下内容应该可以帮助您到达那里:

my_xml = """[your xml above, corrected]"""
data = ET.XML(my_xml.encode('ascii'))
for target in data.xpath("//*[local-name() = 'Unicode'][not(text())]"):
    target.getparent().remove(target)     

print(etree.tostring(data,  xml_declaration=True))

输出:

    <?xml version=\'1.0\' encoding=\'ASCII\'?>\n
<PcGts
    xmlns="http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15 http://schema.primaresearch.org/PAGE/gts/pagecontent/2013-07-15/pagecontent.xsd">
    <Page imageFilename="1.png">
        <TextRegion custom="a">
            <TextLine custom="readingOrder {index:0;}" id="Ar0010001l1">
                <TextEquiv>
                    <Unicode> abc </Unicode>
                </TextEquiv>
            </TextLine>
            <TextLine custom="readingOrder {index:1;}" id="Ad0010100l2">
                <TextEquiv/>
            </TextLine>
        </TextRegion>
    </Page>
</PcGts>