学习爬虫出现错误，找不到原因

使用  python3.7

  vs code

刚弄一半  就出错

    print(div[0]) ----------(这一步显示错误     

发生异常: IndexError

list index out of range

File "D:\Users\python-WEeiliang\Desktop\python练习集\小说.py", line 11, in <module> print(div[0])

import requests
from bs4 import BeautifulSoup

if __name__ == '__main__':
    target = 'https://www.bqkan.com/55_55890/14586139.html'
    req = requests.get(url=target)
    html = req.text
    div_bf = BeautifulSoup(html)
    div = div_bf.find_all('div', class_ = 'listmain')
    print(div[0]) 

原因是所请求网页没有找到该元素，变量div是None。对空的列表索引会报这样错误。

将其中两行改为如下即可：

div_bf = BeautifulSoup(html,'lxml')

div = div_bf.find_all('div', class_='showtxt')

谢谢