python - 如何使用 Beautiful Soup 忽略空标签？

Question

我有这个网页:

text = BeautifulSoup(requests.get('https://www.washingtonpost.com/blogs/on-small-business/post/how-to-breed-big-innovation-inside-a-small-business/2013/03/26/b1a8953e-962a-11e2-9e23-09dce87f75a1_blog.html', timeout=7.00).text)

我有一个漂亮的汤功能，可以拉所有<ul>没有属性且带有 <li> 的标签不包含属性且不带 <a> 的标签标记 child :

def pull_ul(tag):
        return tag.name == 'ul' and not tag.attrs and not tag.li.attrs and not tag.a  
ul_tags = text.find_all(pull_ul)
print ul_tags

当我运行此程序时，我收到一条错误消息:

AttributeError: 'NoneType' object has no attribute 'attrs'

所以我将函数修改为:

def pull_ul(tag):
        return tag.name == 'ul' and not tag.attrs and not tag.a 

输出:

[<ul></ul>, <ul> <li class="report-button" id="flag-spam">Spam</li> <li class="report-button" id="flag-offensive">Offensive</li> <li class="report-button" id="flag-disagree">Disagree</li> <li class="report-button" id="flag-offtopic">Off-Topic</li> </ul>]

这告诉我生成错误的部分是空标签 <ul></ul>

有没有办法重写该函数，使其忽略导致程序出错的所有空标签实例？

Answer 1

如果您只是添加一个额外的检查 tag.li 是否为真会怎样:

def pull_ul(tag):
    return tag.name == 'ul' and \
           not tag.attrs and \
           tag.li and \ # < HERE
           not tag.li.attrs and \
           not tag.a