Python实现抓取城市的PM2.5浓度和排名

#!/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()