如何使用 Python 解析复杂的 XML

Question

我正在将 XML 文件转换为 CSV 或 pandas 文件。 XML 中有各种必要的类别和其他不需要的类别。有没有一种有效的方法来挑选代码中的信息，格式如下。这需要在相对较大的 >10,000 个文档上完成。比如我想获取“family-id”、“data”和

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE patent-document\n  PUBLIC "-//MXW//DTD patent-document XML//EN" 
"http://www.ir-facility.org/dtds/patents/v1.4/patent-document.dtd">
<patent-document ucid="US-20030137706-A1" country="US" doc- 
number="20030137706" kind="A1" lang="EN" family-id="10973265" status="new" 
date-produced="20090605" date="20030724">
  <bibliographic-data>
    <publication-reference ucid="US-20030137706-A1" status="new" 
     fvid="76030147">
  <document-id status="new" format="original">
    <country>US</country>
    <doc-number>20030137706</doc-number>
    <kind>A1</kind>
    <date>20030724</date>
  </document-id>
</publication-reference>
<application-reference ucid="US-18203002-A" status="new" is-representative="NO">
  <document-id status="new" format="epo">
    <country>US</country>
    <doc-number>18203002</doc-number>
    <kind>A</kind>
    <date>20021204</date>
  </document-id>
</application-reference>
<priority-claims status="new">
  <priority-claim ucid="HU-0000532-A" status="new">
    <document-id status="new" format="epo">
      <country>HU</country>
      <doc-number>0000532</doc-number>
      <kind>A</kind>
      <date>20000207</date>
    </document-id>
  </priority-claim>
  <priority-claim ucid="HU-0100016-W" status="new">
  </abstract>
  <description load-source="us" status="new" lang="EN">
     <heading>TECHNICAL FIELD </heading>
     <p>[0001] The object of the invention is a method for the holographic 
     recording of data. In the method a hologram containing the date is 
     recorded in a waveguide layer as an interference between an object beam 
     and a reference beam. The object beam is essentially perpendicular to 
     the plane of the hologram, while the reference beam is coupled in the 
     waveguide. There is also proposed an apparatus for performing the 
     method. The apparatus comprises a data storage medium with a waveguide 
     holographic storage layer, and an optical system for writing and reading 
     the holograms. The optical system comprises means for producing an 
     object beam and a reference beam, and imaging the object beam and a 
     reference beam on the storage medium. </p>
     <heading>BACKGROUND ART </heading>
      <p>[0002] Storage systems realised with tapes stand out from other data 
      storage systems regarding their immense storage capacity. Such systems 
      were used to realise the storage of data in the order of Terabytes. 
      This large storage capacity is achieved partly by the storage density, 
      and partly by the length of the storage tapes. The relative space 
      requirements of tapes are small, because they may be wound up into a 
      very small volume. Their disadvantage is the relatively large random 
      access time. </p>

Answer 1

我强烈建议使用优秀的lxml.etree 库！它非常快，因为它是 C 库 libxml2 和 libxslt 的包装器。

使用示例：

import lxml.etree  

text = '''\
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE patent-document\n  PUBLIC "-//MXW//DTD patent-document XML//EN" 
"http://www.ir-facility.org/dtds/patents/v1.4/patent-document.dtd">
<patent-document ucid="US-20030137706-A1" country="US" doc-number="20030137706" kind="A1" lang="EN" family-id="10973265" status="new" 
date-produced="20090605" date="20030724">
  <bibliographic-data>
    <publication-reference ucid="US-20030137706-A1" status="new" 
     fvid="76030147">
  <document-id status="new" format="original">
    <country>US</country>
    <doc-number>20030137706</doc-number>
    <kind>A1</kind>
    <date>20030724</date>
  </document-id>
</publication-reference>
<application-reference ucid="US-18203002-A" status="new" is-representative="NO">
  <document-id status="new" format="epo">
    <country>US</country>
    <doc-number>18203002</doc-number>
    <kind>A</kind>
    <date>20021204</date>
  </document-id>
</application-reference>
<priority-claims status="new">
  <priority-claim ucid="HU-0000532-A" status="new">
    <document-id status="new" format="epo">
      <country>HU</country>
      <doc-number>0000532</doc-number>
      <kind>A</kind>
      <date>20000207</date>
    </document-id>
  </priority-claim>
  <description load-source="us" status="new" lang="EN">
     <heading>TECHNICAL FIELD </heading>
     <p>[0001] The object of the invention is a method for the holographic 
     recording of data. In the method a hologram containing the date is 
     recorded in a waveguide layer as an interference between an object beam 
     and a reference beam. The object beam is essentially perpendicular to 
     the plane of the hologram, while the reference beam is coupled in the 
     waveguide. There is also proposed an apparatus for performing the 
     method. The apparatus comprises a data storage medium with a waveguide 
     holographic storage layer, and an optical system for writing and reading 
     the holograms. The optical system comprises means for producing an 
     object beam and a reference beam, and imaging the object beam and a 
     reference beam on the storage medium. </p>
     <heading>BACKGROUND ART </heading>
      <p>[0002] Storage systems realised with tapes stand out from other data 
      storage systems regarding their immense storage capacity. Such systems 
      were used to realise the storage of data in the order of Terabytes. 
      This large storage capacity is achieved partly by the storage density, 
      and partly by the length of the storage tapes. The relative space 
      requirements of tapes are small, because they may be wound up into a 
      very small volume. Their disadvantage is the relatively large random 
      access time. </p>
  </description>
</priority-claims>
</bibliographic-data>
</patent-document>
'''.encode('utf-8') # the library wants bytes so we encode
#  ^^ you don't need this if reading from a file

doc = lxml.etree.fromstring(text)

测试：

>>> print(doc.xpath('//patent-document/@family-id'))
['10973265']
>>> print(doc.xpath('//patent-document/@date'))
['20030724']