python学习之常用的内置类(4):python中的XML

XML，一般使用Sax进行分析，下面使用sax来进行分析yahoo天气网页的xml,获取需要的今天和明天的信息.并输出.

from xml.parsers.expat import ParserCreateclass WeatherSaxHandler(object):    def __init__(self):        self._days = 0        self._weather = {}    def start_element(self,name,attrs):        print('sax:start_element:%s attrs:'%name,attrs)        if('city' in attrs or 'country' in attrs):self._weather['city'],self._weather['country'] = attrs['city'],attrs['country']        if(('day' in attrs) and self._days == 0):            self._days += 1            self._weather['today']  = {'text':attrs['text'],'low':int(attrs['low']),'high':int(attrs['high'])}        elif(('day' in attrs) and self._days == 1):            self._days += 1            self._weather['tomorrow'] ={'text':attrs['text'],'low':int(attrs['low']),'high':int(attrs['high'])}    def end_element(self,name):        print('sax:end_element: %s' % name)    def char_data(self,text):        print('sax:char_data: %s' % text)def parse_weather(xml):    weatherparser = WeatherSaxHandler()    parser = ParserCreate()    parser.StartElementHandler = weatherparser.start_element    parser.EndElementHandler = weatherparser.end_element    parser.CharacterDataHandler = weatherparser.char_data    parser.Parse(xml)    return weatherparser._weatherdata = r'''<?xml version="1.0" encoding="UTF-8" standalone="yes" ?><rss version="2.0" xmlns:yweather="http://xml.weather.yahoo.com/ns/rss/1.0" xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">    <channel>        <title>Yahoo! Weather - Beijing, CN</title>        <lastBuildDate>Wed, 27 May 2015 11:00 am CST</lastBuildDate>        <yweather:location city="Beijing" region="" country="China"/>        <yweather:units temperature="C" distance="km" pressure="mb" speed="km/h"/>        <yweather:wind chill="28" direction="180" speed="14.48" />        <yweather:atmosphere humidity="53" visibility="2.61" pressure="1006.1" rising="0" />        <yweather:astronomy sunrise="4:51 am" sunset="7:32 pm"/>        <item>            <geo:lat>39.91</geo:lat>            <geo:long>116.39</geo:long>            <pubDate>Wed, 27 May 2015 11:00 am CST</pubDate>            <yweather:condition text="Haze" code="21" temp="28" date="Wed, 27 May 2015 11:00 am CST" />            <yweather:forecast day="Wed" date="27 May 2015" low="20" high="33" text="Partly Cloudy" code="30" />            <yweather:forecast day="Thu" date="28 May 2015" low="21" high="34" text="Sunny" code="32" />            <yweather:forecast day="Fri" date="29 May 2015" low="18" high="25" text="AM Showers" code="39" />            <yweather:forecast day="Sat" date="30 May 2015" low="18" high="32" text="Sunny" code="32" />            <yweather:forecast day="Sun" date="31 May 2015" low="20" high="37" text="Sunny" code="32" />        </item>    </channel></rss>'''weather = parse_weather(data)assert weather['city'] == 'Beijing', weather['city']assert weather['country'] == 'China', weather['country']assert weather['today']['text'] == 'Partly Cloudy', weather['today']['text']print('today;low:',weather['today']['low'] == 20,weather['today']['low']) assert weather['today']['low'] == 20, weather['today']['low']assert weather['today']['high'] == 33, weather['today']['high']assert weather['tomorrow']['text'] == 'Sunny', weather['tomorrow']['text']assert weather['tomorrow']['low'] == 21, weather['tomorrow']['low']assert weather['tomorrow']['high'] == 34, weather['tomorrow']['high']#print('Weather:', str(weather))