python爬虫爬取网页表格数据

from bs4 import BeautifulSoup import requests import csv import bs4   #检查url地址 def check_link(url):  try:      r = requests.get(url)   r.raise_for_status()   r.encoding = r.apparent_encoding   return r.text  except:   print('无法链接服务器！！！')   #爬取资源 def get_contents(ulist,rurl):  soup = BeautifulSoup(rurl,'lxml')  trs = soup.find_all('tr')  for tr in trs:   ui = []   for td in tr:    ui.append(td.string)   ulist.append(ui)   #保存资源 def save_contents(urlist):  with open("D:/2016年中国企业500强排行榜.csv",'w') as f:   writer = csv.writer(f)   writer.writerow(['2016年中国企业500强排行榜'])   for i in range(len(urlist)):    writer.writerow([urlist[i][1],urlist[i][3],urlist[i][5]]) def main():  urli = []  url = "http://www.maigoo.com/news/463071.html"  rs = check_link(url)  get_contents(urli,rs)  save_contents(urli)  main()