在python 2.7 lxml中使用命名空间访问xml文件中的值 [英] Accesing values in xml file with namespaces in python 2.7 lxml

问题描述

我正在跟踪此链接，以尝试获取多个标签的值:

I'm following this link to try to get values of several tags:

通过"ElementTree"在XML中使用命名空间解析XML

在此链接中，可以像这样访问根标记没有问题:

In this link there is no problem to access to the root tag like this:

import sys
from lxml import etree as ET


doc = ET.parse('file.xml')

namespaces_rdf = {'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'} # add more as needed
namespaces_dcat = {'dcat': 'http://www.w3.org/ns/dcat#'} # add more as needed
namespaces_dct = {'dct': 'http://purl.org/dc/terms/'}

print doc.findall('rdf:RDF', namespaces_rdf)
print doc.findall('dcat:Dataset', namespaces_dcat)
print doc.findall('dct:identifier', namespaces_dct)

输出:

[]
[<Element {http://www.w3.org/ns/dcat#}Dataset at 0x2269b98>]
[]

我只能访问dcat:Dataset，但看不到如何访问rdf:about

I get only access to dcat:Dataset, and I can't see how to access the value of rdf:about

并随后访问dct:identifier

And later access to dct:identifier

当然，一旦我访问了此信息，就需要访问dcat:发行信息

Of course, once I have accessed to this info, I need to acces to dcat:distribution info

这是我的示例文件，它是使用ckanext-dcat生成的:

This is my example file, generated with ckanext-dcat:

<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF
  xmlns:dct="http://purl.org/dc/terms/"
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:dcat="http://www.w3.org/ns/dcat#"
>
  <dcat:Dataset rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01">
    <dct:identifier>ec631628-2f46-4f17-a685-d62a37466c01</dct:identifier>
    <dct:description>FOO-Description</dct:description>
    <dct:title>FOO-title</dct:title>
    <dcat:keyword>keyword1</dcat:keyword>
    <dcat:keyword>keyword2</dcat:keyword>
    <dct:issued rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2014-10-08T08:55:04.566618</dct:issued>
    <dct:modified rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2015-06-25T11:04:10.328902</dct:modified>
    <dcat:distribution>
      <dcat:Distribution rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01/resource/f5707551-6bf3-468f-9a96-b4184cc51d1f">
        <dct:title>FOO-title-1</dct:title>
        <dct:description>FOO-Description-1</dct:description>
        <dcat:accessURL>http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01/resource/f5707551-6bf3-468f-9a96-b4184cc51d1f/download/myxls.xls</dcat:accessURL>
        <dct:format>XLS</dct:format>
      </dcat:Distribution>
    </dcat:distribution>
    <dcat:distribution>
      <dcat:Distribution rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01/resource/74c1acc8-b2b5-441b-afb2-d072d0d00a7f">
        <dct:format>XLS</dct:format>
        <dct:title>FOO-title-2</dct:title>
        <dct:description>FOO-Description-2</dct:description>
        <dcat:accessURL>http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01/resource/74c1acc8-b2b5-441b-afb2-d072d0d00a7f/download/myxls.xls</dcat:accessURL>
      </dcat:Distribution>
    </dcat:distribution>
  </dcat:Dataset>
</rdf:RDF>

关于如何访问此信息的任何想法?? 谢谢

Any idea on how to access this info?? Thanks

更新: 好吧，我需要在以下位置访问 rdf:about :

UPDATE: Well, I need to access rdf:about in:

<dcat:Dataset rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01">

因此，此代码取自:

使用lxml解析xml-提取元素值

for node in doc.xpath('//dcat:Dataset', namespaces=namespaces):
   # Iterate over attributes
   for attrib in node.attrib:
            print '@' + attrib + '=' + node.attrib[attrib]

我得到以下输出:

[<Element {http://www.w3.org/ns/dcat#}Dataset at 0x23d8ee0>]
@{http://www.w3.org/1999/02/22-rdf-syntax-ns#}about=http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01

所以，问题是:

我如何询问该属性是否为约以采用此值，因为在其他文件中，我有多个标签.

How can I ask if the attribute is about to take this value, because in other files I have several tags.

更新2:修正了我如何获得价值(克拉克符号)

UPDATE 2: Fixed how I get about value (clark notations)

for node in doc.xpath('//dcat:Dataset', namespaces=namespaces):
   # Iterate over attributes
   for attrib in node.attrib:
      if attrib.endswith('about'):
        #do my jobs

好了，快要完成了，但是我还有最后一个问题:我需要知道何时访问我的

<dct:title>

我属于:

<dcat:Dataset rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01">
       <dct:title>FOO-title</dct:title>

<dcat:Distribution rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01/resource/f5707551-6bf3-468f-9a96-b4184cc51d1f">
        <dct:title>FOO-title-1</dct:title>

<dcat:Distribution rdf:about="http://www.myweb.com/dataset/ec631628-2f46-4f17-a685-d62a37466c01/resource/74c1acc8-b2b5-441b-afb2-d072d0d00a7f">
        <dct:title>FOO-title-2</dct:title>

如果我做这样的事情，我会得到:

If I do something like this I get:

for node in doc.xpath('//dct:title', namespaces=namespaces):
   print node.tag, node.text

{http://purl.org/dc/terms/}title FOO-title
{http://purl.org/dc/terms/}title FOO-title-1
{http://purl.org/dc/terms/}title FOO-title-2

谢谢

推荐答案

使用xpath()方法和namespaces命名参数:

namespaces = {
    'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
    'dcat': 'http://www.w3.org/ns/dcat#',
    'dct': 'http://purl.org/dc/terms/'
}

print(doc.xpath('//rdf:RDF', namespaces=namespaces))
print(doc.xpath('//dcat:Dataset', namespaces=namespaces))
print(doc.xpath('//dct:identifier', namespaces=namespaces))

这篇关于在python 2.7 lxml中使用命名空间访问xml文件中的值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！