從http://www.pm25.com/shenzhen.html抓取北京，深圳，上海，廣州，成都的pm2.5指數，並按照空氣質量從優到差排序，保存在txt文檔裏
代碼如下：
#coding=utf-8
from selenium import webdriver
from time import sleep
class PM:
def __init__(self):
self.dr = webdriver.Chrome()
self.pm25_info = self.get_pm25_info()
def get_pm25_info(self):
city_list = ['beijing','shenzhen','shanghai','guangzhou','chengdu']
pm_info_list = []
i = 0
while i < len(city_list):
self.dr.get('http://www.pm25.com/'+city_list[i]+'.html')
sleep(3)
city_name = self.dr.find_element_by_css_selector('.bi_loaction_city').text #定位城市名字
pm_exp = self.dr.find_element_by_css_selector('.pm25_span').text #定位PM2.5指數
air_num = self.dr.find_element_by_css_selector('.bi_aqiarea_num').text #定位AQI指數
air_quality = self.dr.find_element_by_css_selector('.bi_aqiarea_right span').text #定位空氣質量描述
pm_info_list.append((city_name, pm_exp, air_num, air_quality))
i += 1
pm_info_list.sort(key=lambda x:float(x[2])) #按AQI指數排序(AQI指數決定了空氣質量的優良)
return pm_info_list
def get_pm_info_file(self):
self.file_title = '北上廣深成五地PM2.5數據信息'
self.file = open(self.file_title + '.txt', 'wb')
self.floor = 1
for item in self.pm25_info:
separate_line = '**********' + 'TOP' + str(self.floor) + '**********\n'
self.file.write(separate_line.encode('utf-8'))
self.file.write(('城市：' + item[0] + '\n'
'PM2.5指數：' + item[1] + ' '+ '微克/立方米' + '\n'
'AQI指數：' + item[2] + '\n'
'空氣質量：' + item[3]+ '\n').encode('utf-8'))
self.floor += 1
self.file.close()
def quit(self):
self.dr.quit()
if __name__ == '__main__':
pm_info = PM()
pm_info.get_pm_info_file()
pm_info.quit()網頁如下：
生成txt如下：
