在python中使用regex匹配html标记

Question

str="<p class=\"drug-subtitle\"><b>Generic Name:</b> albuterol inhalation (al BYOO ter all)<br><b>Brand Names:</b> <i>Accuneb, ProAir HFA, Proventil, Proventil HFA, ReliOn Ventolin HFA, Ventolin HFA</i></p>"

br=re.match("<p> class=\"drug-subtitle\"[^>]*>(.*?)</p>",str)

br无返回

我使用的正则表达式有什么错误？在

Answer 1

我强烈建议您可以使用一个DOM解析器库，例如lxml和例如cssselect一起使用。在

示例：

>>> from lxml.html import fromstring
>>> html = """<p class="drug-subtitle"><b>Generic Name:</b> albuterol inhalation (al BYOO ter all)<br><b>Brand Names:</b> <i>Accuneb, ProAir HFA, Proventil, Proventil HFA, ReliOn Ventolin HFA, Ventolin HFA</i></p>"""
>>> doc = fromstring(html)
>>> "".join(filter(None, (e.text for e in doc.cssselect(".drug-subtitle")[0])))
'Generic Name:Brand Names:Accuneb, ProAir HFA, Proventil, Proventil HFA, ReliOn Ventolin HFA, Ventolin HFA'

Answer 2

固定的正则表达式就是这个。在我指出的第二行，你会发现它对你不起作用的地方。我使用findall()方便地访问屏幕上所有匹配的组。在

print re.findall('<p class="drug-subtitle"[^>]*>(.*?)</p>',input)
                    ^ you had a > character here

但是，BeautifulSoup将是这类操作的简单选择：

^{pr2}$

Answer 3

如果有输入：

'<p class="drug-subtitle"><b>Generic Name:</b> albuterol inhalation (al BYOO ter all)<br><b>Brand Names:</b> <i>Accuneb, ProAir HFA, Proventil, Proventil HFA, ReliOn Ventolin HFA, Ventolin HFA</i></p>' 

你想检查一下：

^{pr2}$

存在于输入中，要使用的正则表达式是：

\<p\sclass=\"drug-subtitle\"[^>]*>(.*?)\<\/p\> 

说明：

\< matches the character < literally
p matches the character p literally (case sensitive)
\s match any white space character [\r\n\t\f ]
class= matches the characters class= literally (case sensitive)
\" matches the character " literally
drug-subtitle matches the characters drug-subtitle literally (case sensitive)
\" matches the character " literally
[^>]* match a single character not present in the list below
    Quantifier: Between zero and unlimited times, as many times as possible,
               giving back as needed.
    > a single character in the list &gt; literally (case sensitive)
> matches the character > literally
1st Capturing group (.*?)
    .*? matches any character (except newline)
        Quantifier: Between zero and unlimited times, as few times as possible,
                    expanding as needed.
\< matches the character < literally
\/ matches the character / literally
p matches the character p literally (case sensitive)
\> matches the character > literally

所以正则表达式中的问题是：

1. 在<；p>；中应该没有“>；”。在
2. 在<；/p>；中，应在“<；，/，>；”字符前面添加“\”来转义它们。在

希望这有帮助。在