用Python处理XML真的很简单吗?

你想要薄的贴面吗?那很容易做。首先尝试以下围绕ElementTree的简单包装:

# geetree.py
import xml.etree.ElementTree as ET

class GeeElem(object):
    """Wrapper around an ElementTree element. a['foo'] gets the
       attribute foo, a.foo gets the first subelement foo."""
    def __init__(self, elem):
        self.etElem = elem

    def __getitem__(self, name):
        res = self._getattr(name)
        if res is None:
            raise AttributeError, "No attribute named '%s'" % name
        return res

    def __getattr__(self, name):
        res = self._getelem(name)
        if res is None:
            raise IndexError, "No element named '%s'" % name
        return res

    def _getelem(self, name):
        res = self.etElem.find(name)
        if res is None:
            return None
        return GeeElem(res)

    def _getattr(self, name):
        return self.etElem.get(name)

class GeeTree(object):
    "Wrapper around an ElementTree."
    def __init__(self, fname):
        self.doc = ET.parse(fname)

    def __getattr__(self, name):
        if self.doc.getroot().tag != name:
            raise IndexError, "No element named '%s'" % name
        return GeeElem(self.doc.getroot())

    def getroot(self):
        return self.doc.getroot()

>>> import geetree
>>> t = geetree.GeeTree('foo.xml')
>>> t.xml_api_reply.weather.forecast_information.city['data']
'Mountain View, CA'
>>> t.xml_api_reply.weather.current_conditions.temp_f['data']
'68'

lxml已经被提到。你也可以去看看 lxml.objectify

>>> from lxml import objectify
>>> tree = objectify.fromstring(your_xml)
>>> tree.weather.attrib["module_id"]
'0'
>>> tree.weather.forecast_information.city.attrib["data"]
'Mountain View, CA'
>>> tree.weather.forecast_information.postal_code.attrib["data"]
'94043'

我强烈建议使用lxml.etree和xpath来解析和分析数据。下面是一个完整的例子。我截断了xml以使其更易于阅读。

import lxml.etree

s = """<?xml version="1.0" encoding="utf-8"?>
<xml_api_reply version="1">
  <weather module_id="0" tab_id="0" mobile_row="0" mobile_zipped="1" row="0" section="0" >
    <forecast_information>
      <city data="Mountain View, CA"/> <forecast_date data="2010-06-23"/>
    </forecast_information>
    <forecast_conditions>
      <day_of_week data="Sat"/>
      <low data="59"/>
      <high data="75"/>
      <icon data="/ig/images/weather/partly_cloudy.gif"/>
      <condition data="Partly Cloudy"/>
    </forecast_conditions>
  </weather>
</xml_api_reply>"""

tree = lxml.etree.fromstring(s)
for weather in tree.xpath('/xml_api_reply/weather'):
    print weather.find('forecast_information/city/@data')[0]
    print weather.find('forecast_information/forecast_date/@data')[0]
    print weather.find('forecast_conditions/low/@data')[0]
    print weather.find('forecast_conditions/high/@data')[0]

this tutorial .

它的工作方式和你描述的非常相似。

另一方面。元素树 find*() 方法可以为您提供90%的支持,并使用Python打包。

如果您不介意使用第三方库,那么 BeautifulSoup

>>> from BeautifulSoup import BeautifulStoneSoup
>>> soup = BeautifulStoneSoup('''<snip>''')
>>> soup.xml_api_reply.weather.current_conditions.temp_f['data']
u'68'

xml.parsers.expat

我发现如下 python-simplexml 模块,在作者试图从PHP中获得接近SimpleXML的东西时,它确实是一个 small wrapper around ElementTree . 它不到100行,但似乎做到了要求的:

>>> import SimpleXml
>>> x = SimpleXml.parse(urllib.urlopen('http://www.google.com/ig/api?weather=94043'))
>>> print x.weather.current_conditions.temp_f['data']
58

suds项目提供了一个Web服务客户机库,它几乎完全按照您所描述的那样工作——向它提供一个wsdl,然后使用工厂方法来创建定义的类型(并处理响应!)。

如果你还没有,我建议你调查一下 DOM API for Python

它可能比您描述的要复杂一点,但这是因为它试图保留XML标记中隐含的所有信息,而不是因为设计不当。