#!/usr/bin/env python # -*- coding: utf-8 -*- # by ustcwq import urllib2 import threading from time import ctime from bs4 import BeautifulSoup def getPM25(cityname):     site = 'http://www.pm25.com/' + cityname + '.html'     html = urllib2.urlopen(site)     soup = BeautifulSoup(html)     city = soup.find(class_ = 'bi_loaction_city')   # 城市名称     aqi = soup.find("a",{"class","bi_aqiarea_num"})  # AQI指数     quality = soup.select(".bi_aqiarea_right span")  # 空气质量等级     result = soup.find("div",class_ ='bi_aqiarea_bottom')   # 空气质量描述     print city.text + u'AQI指数：' + aqi.text + u'\n空气质量：' + quality[0].text + result.text     print '*'*20 + ctime() + '*'*20 def one_thread():   # 单线程     print 'One_thread Start: ' + ctime() + '\n'     getPM25('hefei')     getPM25('shanghai') def two_thread():   # 多线程     print 'Two_thread Start: ' + ctime() + '\n'     threads = []     t1 = threading.Thread(target=getPM25,args=('hefei',))     threads.append(t1)     t2 = threading.Thread(target=getPM25,args=('shanghai',))     threads.append(t2)     for t in threads:         # t.setDaemon(True)         t.start() if __name__ == '__main__':     one_thread()     print '\n' * 2     two_thread()