城市天气查询（Python）

# coding: cp936

"""
    查询城市天气情况
    信息来源网 weather.news.sohu.com
    Author : 寒江风
    QQ : 84640008
    Date : 2006-09-05
"""
import urllib
import re

def main():
    # Show Information
    print '中国城市天气查询'

    # Get Parameters
    city = raw_input('请输入您要查询天气的城市名字(如汕头,广州...) : ')

    # Request For The Web Page
    params = urllib.urlencode({'city':city})
    webpage = urllib.urlopen('http://weather.news.sohu.com/city_inc.php?%s' % params)
    webdata = webpage.read().replace('\n', '')

    # Match The Useful Information
    pattern = re.compile('<td class=blu01>([^<]*)<br>([^<]*)<br>([^<]*)<br>([^<]*)')
    x = 0
    for weather in pattern.findall(webdata):
        if x == 0:
            print '今日天气预报:'
        elif x == 1:
            print '明日天气预报:'
        else:
            print '后日天气预报:'
        for i in range(4):
            print weather[i].strip()
        x += 1

if __name__ == '__main__':
    main()

思想:通过网页链接提交进行天气查询，获取查询结果，然后进行正则匹配，提取有用信息