仅当有两个类并且共享相同的第一个时才选择元素

Question

我在HTML中有这些元素我想解析：

<td class="line"> GARBAGE </td>
<td class="line text"> I WANT THAT </td>
<td class="line heading"> I WANT THAT </td>
<td class="line"> GARBAGE </td>

如何制作 CSS select 或 select 具有属性 class 行和 class 其他内容（可能是标题、文本或其他任何东西）但不只属性 class 行？

我试过：

 td[class=line.*]
 td.line.*
 td[class^=line.]

编辑

我正在使用 Python 和 BeautifulSoup:

url = 'http://www.somewebsite'
res = requests.get(url)
res.raise_for_status()
DicoSoup = bs4.BeautifulSoup(res.text, "lxml")
elems = DicoSoup.select('body div#someid tr td.line')

我正在研究修改最后一块，即 td.line 到 td.line.whateverotherclass 之类的东西（但不是单独 td.line 否则我的 selector 就足够了）

Answer 1

您可以为 class 选择器链接 CSS classes。

.line {
  color: green;
}
.line.text {
  color: red;
}
.line.heading {
  color: blue;
}

<p class="line">GARBAGE</p>
<p class="line text">I WANT THAT</p>
<p class="line heading">I WANT THAT</p>
<p class="line">GARBAGE</p>

Answer 2

什么@BoltClock suggested is generally a correct way to approach the problem with CSS selectors. The only problem is that BeautifulSoup supports a limited number of CSS selectors. For instance, not() selector is :not(.supported) at the moment.

您可以使用 "starts-with" 选择器来解决它，以检查 class 是否以 line 开头，然后是 space（它非常脆弱，但可以在您的样本数据）：

for td in soup.select("td[class^='line ']"):
    print(td.get_text(strip=True))

或者，您可以使用 find_all() 并使用 searching function 检查 class 属性以具有 line 和其他一些 class 来解决它：

from bs4 import BeautifulSoup

data = """
<table>
    <tr>
        <td class="line"> GARBAGE </td>
        <td class="line text"> I WANT THAT </td>
        <td class="line heading"> I WANT THAT </td>
        <td class="line"> GARBAGE </td>
    </tr>
</table>"""
soup = BeautifulSoup(data, 'html.parser')

for td in soup.find_all(lambda tag: tag and tag.name == "td" and
                                    "class" in tag.attrs and "line" in tag["class"] and
                                    len(tag["class"]) > 1):
    print(td.get_text(strip=True))

打印：

I WANT THAT
I WANT THAT

仅当有两个类并且共享相同的第一个时才选择元素

Selecting elements only if have two classes and share the same first one

html

python

beautifulsoup

css-selectors

html-parsing

仅当有两个 类 并且共享相同的第一个时才选择元素

Selecting elements only if have two classes and share the same first one

html

python

beautifulsoup

css-selectors

html-parsing

仅当有两个类并且共享相同的第一个时才选择元素