Question

我希望使用Python解析可用的Gutenberg目录here。我在网络抓取和解析HTML方面经验丰富，但这种格式让我望而却步。我尝试过使用lxml etree和以下尝试使用RDFlib：

path = 'epub/10/pg%s.rdf'
g = rdflib.Graph()
g.parse(path)
s = g.serialize(format='nt')
print(g)

我正在寻找各种元数据值（标题，作者，Gutenberg网址等）。我在下面提供了一个示例文件。

<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF xml:base="http://www.gutenberg.org/"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
  xmlns:cc="http://web.resource.org/cc/"
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:dcterms="http://purl.org/dc/terms/"
  xmlns:pgterms="http://www.gutenberg.org/2009/pgterms/"
  xmlns:dcam="http://purl.org/dc/dcam/"
>
  <cc:Work rdf:about="">
    <cc:license rdf:resource="http://www.gnu.org/licenses/gpl.html"/>
    <rdfs:comment>Archives containing the RDF files for *all* our books can be downloaded at
            http://www.gutenberg.org/wiki/Gutenberg:Feeds#The_Complete_Project_Gutenberg_Catalog</rdfs:comment>
  </cc:Work>
  <pgterms:ebook rdf:about="ebooks/100">
    <dcterms:title>The Complete Works of William Shakespeare</dcterms:title>
    <pgterms:bookshelf>
      <rdf:Description rdf:nodeID="Ncc8361d84fc142969cf27b77ac8d0c24">
        <rdf:value>Plays</rdf:value>
        <dcam:memberOf rdf:resource="2009/pgterms/Bookshelf"/>
      </rdf:Description>
    </pgterms:bookshelf>
    <dcterms:issued rdf:datatype="http://www.w3.org/2001/XMLSchema#date">1994-01-01</dcterms:issued>
    <dcterms:publisher>Project Gutenberg</dcterms:publisher>
    <dcterms:rights>Copyrighted. Read the copyright notice inside this book for details.</dcterms:rights>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/files/100/100.txt">
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">5589917</dcterms:extent>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2014-08-29T12:08:52</dcterms:modified>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N19fd61f986a94cc18f5dce9ed07e8517">
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">text/plain; charset=us-ascii</rdf:value>
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
          </rdf:Description>
        </dcterms:format>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:license rdf:resource="license"/>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.kindle.images">
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N0ee902d343e44cb5a8f639fa55fc6334">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">application/x-mobipocket-ebook</rdf:value>
          </rdf:Description>
        </dcterms:format>
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">9509392</dcterms:extent>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:18:40.171080</dcterms:modified>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:subject>
      <rdf:Description rdf:nodeID="N0e2195113aa34bf7abfe001edf6a03a2">
        <rdf:value>English drama -- Early modern and Elizabethan, 1500-1600</rdf:value>
        <dcam:memberOf rdf:resource="http://purl.org/dc/terms/LCSH"/>
      </rdf:Description>
    </dcterms:subject>
    <dcterms:creator>
      <pgterms:agent rdf:about="2009/agents/65">
        <pgterms:name>Shakespeare, William</pgterms:name>
        <pgterms:birthdate rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">1564</pgterms:birthdate>
        <pgterms:deathdate rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">1616</pgterms:deathdate>
        <pgterms:alias>Shakspeare, William</pgterms:alias>
        <pgterms:webpage rdf:resource="http://en.wikipedia.org/wiki/William_Shakespeare"/>
        <pgterms:alias>Shakspere, William</pgterms:alias>
      </pgterms:agent>
    </dcterms:creator>
    <dcterms:subject>
      <rdf:Description rdf:nodeID="Ncb26996951d44761901e30445fc8a9dc">
        <dcam:memberOf rdf:resource="http://purl.org/dc/terms/LCC"/>
        <rdf:value>PR</rdf:value>
      </rdf:Description>
    </dcterms:subject>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/files/100/100.zip">
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">2035857</dcterms:extent>
        <dcterms:format>
          <rdf:Description rdf:nodeID="Nb4f5881241fd42e9a0f8a07cb1462008">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">application/zip</rdf:value>
          </rdf:Description>
        </dcterms:format>
        <dcterms:format>
          <rdf:Description rdf:nodeID="Nc3c66052298f482488fb8f13215f92ba">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">text/plain; charset=us-ascii</rdf:value>
          </rdf:Description>
        </dcterms:format>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2014-08-29T12:09:20</dcterms:modified>
      </pgterms:file>
    </dcterms:hasFormat>
    <pgterms:downloads rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">4605</pgterms:downloads>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.epub.noimages">
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">2376083</dcterms:extent>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:18:13.998200</dcterms:modified>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N9dc27629e3164dba98c659dcaf47c7fe">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">application/epub+zip</rdf:value>
          </rdf:Description>
        </dcterms:format>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.html.noimages">
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">6944416</dcterms:extent>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:18:00.715792</dcterms:modified>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N7140e760a0f14ae4ba4b027bd7f7f4f6">
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">text/html</rdf:value>
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
          </rdf:Description>
        </dcterms:format>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.kindle.noimages">
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">9509383</dcterms:extent>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N34666f5ebdd8461ca1c6b8cfba5103e5">
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">application/x-mobipocket-ebook</rdf:value>
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
          </rdf:Description>
        </dcterms:format>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:19:07.134922</dcterms:modified>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.epub.images">
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">2376084</dcterms:extent>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N1e32eb8531504d378e05acb6440d24b0">
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">application/epub+zip</rdf:value>
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
          </rdf:Description>
        </dcterms:format>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:18:09.062427</dcterms:modified>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.rdf">
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-28T05:00:49.076168</dcterms:modified>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N1d915c961af44ab7ac9c71e7ec068bde">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">application/rdf+xml</rdf:value>
          </rdf:Description>
        </dcterms:format>
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">11275</dcterms:extent>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:language>
      <rdf:Description rdf:nodeID="N5ff08142477c4bfeb3bac48c18ba23a4">
        <rdf:value rdf:datatype="http://purl.org/dc/terms/RFC4646">en</rdf:value>
      </rdf:Description>
    </dcterms:language>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.txt.utf-8">
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:17:42.102580</dcterms:modified>
        <dcterms:format>
          <rdf:Description rdf:nodeID="N98845b3d16bd42d787e9d7cba42bf44b">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">text/plain</rdf:value>
          </rdf:Description>
        </dcterms:format>
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">5589889</dcterms:extent>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
      </pgterms:file>
    </dcterms:hasFormat>
    <dcterms:type>
      <rdf:Description rdf:nodeID="N47bb369dd96248ffb1f412145cdb0713">
        <rdf:value>Text</rdf:value>
        <dcam:memberOf rdf:resource="http://purl.org/dc/terms/DCMIType"/>
      </rdf:Description>
    </dcterms:type>
    <dcterms:hasFormat>
      <pgterms:file rdf:about="http://www.gutenberg.org/ebooks/100.html.images">
        <dcterms:extent rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">6944416</dcterms:extent>
        <dcterms:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-04-01T01:17:55.634002</dcterms:modified>
        <dcterms:format>
          <rdf:Description rdf:nodeID="Nd1733441ad824cff97a5d9ad50f0307b">
            <dcam:memberOf rdf:resource="http://purl.org/dc/terms/IMT"/>
            <rdf:value rdf:datatype="http://purl.org/dc/terms/IMT">text/html</rdf:value>
          </rdf:Description>
        </dcterms:format>
        <dcterms:isFormatOf rdf:resource="ebooks/100"/>
      </pgterms:file>
    </dcterms:hasFormat>
  </pgterms:ebook>
  <rdf:Description rdf:about="http://en.wikipedia.org/wiki/William_Shakespeare">
    <dcterms:description>Wikipedia</dcterms:description>
  </rdf:Description>
</rdf:RDF>

Answer 1

你能用正则表达式解析它吗？例如

import re
title = re.search("<dcterms:title>([^<]*)", xml)

编辑如果您想使用xml解析器执行此操作，则需要声明命名空间（在xml文件的顶部定义）：

import xml.etree.ElementTree as et
tree = et.parse(path)
ns = {"dcterms": "http://purl.org/dc/terms/"}
title = tree.find(".//dcterms:title", ns)

Answer 2

我知道你已经快速获得了快捷方式，但我想我也简要说明了基于RDF的方法，你已经非常接近了：你已经设法创造了一个Graph对象并将RDF文件加载到其中。前进的方法是查询该Graph对象以获取您感兴趣的属性。

举一个简单的例子，要检索ID为http://www.gutenberg.org/ebooks/100的电子书的标题，你可以这样做（警告：我没有Python程序员，所以可能会有错误）：

from rdflib import URIRef, Namespace

id = URIRef("http://www.gutenberg.org/ebooks/100")

# we create a Namespace for the relationship names, to make easy to reuse
pgterms = Namespace("http://www.gutenberg.org/2009/pgterms/")

# print out the object value(s) of the 'title' relation for ebook 100.
for title in g.objects(id, pgterms.title)) 
    print(title)

请注意，我可能在这里错过了一些有效的快捷方式 - 我不太了解RDFLib，只是通过查看他们的documentation几分钟来编造这个例子。很可能直接从您之前加载的图形中获取该命名空间，而不必像这样手动定义它们。

一般原则是这样的：RDF是一个图形，包含单个语句，带有主题，谓词和对象。您可以通过查询该图表来使用它。上面是一个非常简单的查询，只检索单个主题和单个关系的值，但当然你可以做循环，路径，列表等。

在Python中解析Gutenberg的RDF

2 个答案: