Python正前pression为美味的汤 [英] Python regular expression for Beautiful Soup

问题描述

我是用美丽的汤拔出具体div标签，似乎我无法使用
简单的字符串匹配。

I am using Beautiful Soup to pull out specific div tags, and it seems I can't use simple string matching.

该页面有一些标签的形式

The page has some tags in the form of

<div class="comment form new"...> 

我想忽略，也有些标签的形式

which I want to ignore, and also some tags in the form of

<div class="comment comment-xxxx..."> 

其中x重新present任意长度的整数，椭圆重新presents用空格分隔的其他值（即我不关心）的任意数量。我想不通的
正确的正则表达式前pression，尤其是因为我从来没有使用Python的重类。

where the x's represent an integer of arbitrary length, and the ellipses represents an arbitrary number of other values separated by white spaces (that I'm not concerned about). I can't figure out the correct regex expression, especially since I've never used python's re class.

使用

soup.find_all(class_="comment") 

查找以单词注释的所有标签。我已经尝试使用

finds all tags starting with the word comment. I have tried using

soup.find_all(class_=re.compile(r'(comment)( )(comment)'))
soup.find_all(class_=re.compile(r'comment comment.*'))

和许多其他的变化，但我想我缺少明显的东西在这里如何的正则表达式前pressions或匹配（）的工作。谁能帮我？

and lots of other variations, but I think I'm missing something obvious here about how regex expressions or match() work. Can anyone help me out?

推荐答案

我想我知道了：

>>> [div['class'] for div in soup.find_all('div')]
[['comment', 'form', 'new'], ['comment', 'comment-xxxx...']]

注意，不像BS3相当于它不是这样的：

Notice that, unlike the equivalent in BS3, it's not this:

['comment form new', 'comment comment-xxxx...']

这就是为什么你的正则表达式不匹配。

And that's why your regexps won't match.

但你可以匹配，例如，这样的：

But you can match, e.g., this:

>>> soup.find_all('div', class_=re.compile('comment-'))
[<div class="comment comment-xxxx..."></div>]

需要注意的是BS确实 re.search 相当于，没有 re.match ，所以你不需要'评论 - *。。当然，如果你想匹配评论-12345而不是评论-OF-另一个实物你 ð希望，例如，'comment- \\ D + 。

Note that BS does the equivalent of re.search, not re.match, so you don't need 'comment-.*'. Of course if you want to match 'comment-12345' but not 'comment-of-another-kind you'd want, e.g., 'comment-\d+'.

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