list index out of range错误

div_list = html.xpath('//div[@class="detail"]')
for div in div_list:
    # 获取书名
    title = div.xpath('./div[@class="title"]/a/text()')[0]
    # 获取评分
    rating_nums = div.xpath('.//span[@class="rating_nums"]/text()')[0]
    #获取评论
    pinglun = div.xpath('.//span[@class="pl"]/text()')[0]
    print(title, rating_nums, pinglun)片

当我们这个有个空的列表的时候。把这个里面内容取出来，他就会出现

Traceback (most recent call last):
File “E:/pythonwork/第三阶段/day06/豆瓣阅读爬取.py”, line 40, in
rating_nums = div.xpath(’.//span[@class=“rating_nums”]/text()’)[0]
IndexError: list index out of range（超出范围）

这样的错误。

解决的方式：使用一个if语句来判断这个是否是空列表：

div_list = html.xpath('//div[@class="detail"]')
for div in div_list:
    # 获取书名
    title = div.xpath('./div[@class="title"]/a/text()')[0]
    # 获取评分
    rating_nums = div.xpath('.//span[@class="rating_nums"]/text()')[0]
    if rating_nums == []:
          rating_nums = ''
    else:
        rating_nums = div.xpath('.//span[@class="rating_nums"]/text()')[0]

    #获取评论
    pinglun = div.xpath('.//span[@class="pl"]/text()')
    if pinglun == []:
        pinglun = ''
    else:
        pinglun = div.xpath('.//span[@class="rating_nums"]/text()')[0]
    print(title, rating_nums, pinglun)

这样就可以解决了。