python对xpath的支持

 介绍python的Xpath的Python开元项目:

1.libxml2-python-2.6.4.tar.gz

安装：下载对应python版本的软件包à解压àpython setup.py install

例一：

import libxml2

def text() :

doc = libxml2.parseFile('/tmp/books.xml')

for book in doc.xpathEval('/bookstore/book') :

        print book.content

doc.freeDoc()

例二

import libxml2

doc = libxml2.parseFile('/tmp/books.xml')

doc.xpathEval('/bookstore/book[1]/price + /bookstore/book[1]/price ')

doc.xpathEval('/bookstore/book[2]/price < 0')

doc.freeDoc()

例三

import libxml2

doc = libxml2.parseFile('/tmp/books.xml')

doc.xpathEval('child::book') #返回的结果是什么？为什么

doc.xpathEval('child::bookstore')

doc.xpathEval('descendant::bookstore')

doc.freeDoc()

例四： 

import libxml2

doc = libxml2.parseFile('/tmp/books.xml')

doc.xpathEval('/bookstore/book[price>35.00]')[0].content

doc.xpathEval('/bookstore/book[last()]')

doc.freeDoc()

2.Google的开源项目，python官方网站上推荐的xpath项目，版本为0.1

Http://py-dom-xpath.googlecode.com/files/py-dom-xpath-0.1.tar.gz

安装：下载软件包à解压àpython setup.py install

例一

import xpath

import xml.dom.minidom

xml = xml.dom.minidom.parse('/tmp/books.xml')

doc = xml.documentElement

xpath.find('/bookstore/book[1]', doc)[0].toxml()

xpath.find('/bookstore', doc)

例二

import xpath

import xml.dom.minidom

xml = xml.dom.minidom.parse('/tmp/books.xml')

doc = xml.documentElement

context = xpath.XPathContext()

context.variables['max'] = 100

context.variables['min'] = 4

context.findvalues('//book[price>=$min and price<=$max]', doc)

还可以根据命名空间查询

详细参考文档：http://py-dom-xpath.googlecode.com/svn/trunk/doc/index.html

3.用python中自带的库解析xml

from xml.etree import ElementTree as XmlTree

xmlDoc = XmlTree.parse('/tmp/books.xml')

xmlRoot = xmlDoc.getroot()

value = xmlRoot.find('book/price').text

print value