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好的开始我知道我不应该使用正则表达式来解析 HTML,因为它不是很可靠,不是 100% 安全等。但是,这只是正则表达式的学习练习。

所以我的例子使用了 bbc 网站http://www.bbc.co.uk/sport/football/premier-league/table

该项目正在解析第一个表的 tbody。我正在尝试进行搜索,以便只返回与搜索值匹配的元素。例如,给定搜索“manc”,我想要曼彻斯特城和曼彻斯特联队的 tr 标签(从 url 匹配)。

到目前为止,我所拥有的是<tr\b[^>]*>(.*?)manc(.*?)</tr>从第一个 tr 到 man city 之后的结束 tr 匹配,然后返回 man utd 的预期结果。谁能指出我在这个正则表达式上出了什么问题。

编辑:来源(修剪)

<tbody id="trc-20-118996114-3">
  <tr id="team-138824012" class="team first">
    <td class="statistics"></td>
    <td class='position'>
      <span class='moving-up'>Moving up</span>
      <span class='position-number'>1</span>
    </td>
    <td class="team-name">
      <a href='http://www.bbc.co.uk/sport/football/teams/arsenal'>Arsenal</a>
    </td>
    <td class="played">0</td>

    <td class="home-won">
      <span>0</span>
    </td>
    <td class="home-drawn">0</td>
    <td class="home-lost">0</td>
    <td class="home-for">0</td>
    <td class="home-against">0</td>
    <td class="away-won">
      <span>0</span>
    </td>
    <td class="away-drawn">0</td>
    <td class="away-lost">0</td>
    <td class="away-for">0</td>
    <td class="away-against">0</td>
    <td class="goal-difference">0</td>
    <td class="points">0</td>
    <td class="last-10-games">
      <ol>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win last" title="Win">
          <span>Win</span>
        </li>
      </ol>
    </td>
    <td class="status">
      <a class="report" href="http://www.bbc.co.uk/sport/0/football/17973141">Report</a>
    </td>
  </tr>
  <tr id="team-137316633" class="team">
    <td class="statistics"></td>
    <td class='position'>
      <span class='moving-up'>Moving up</span>
      <span class='position-number'>2</span>
    </td>
    <td class="team-name">
      <a href='http://www.bbc.co.uk/sport/football/teams/aston-villa'>Aston Villa</a>
    </td>
    <td class="played">0</td>

    <td class="home-won">
      <span>0</span>
    </td>
    <td class="home-drawn">0</td>
    <td class="home-lost">0</td>
    <td class="home-for">0</td>
    <td class="home-against">0</td>
    <td class="away-won">
      <span>0</span>
    </td>
    <td class="away-drawn">0</td>
    <td class="away-lost">0</td>
    <td class="away-for">0</td>
    <td class="away-against">0</td>
    <td class="goal-difference">0</td>
    <td class="points">0</td>
    <td class="last-10-games">
      <ol>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="loss last" title="Loss">
          <span>Loss</span>
        </li>
      </ol>
    </td>
    <td class="status">
      <a class="report" href="http://www.bbc.co.uk/sport/0/football/17973120">Report</a>
    </td>
  </tr>
  <tr id="team-137318151" class="team">
    <td class="statistics"></td>
    <td class='position'>
      <span class='moving-down'>Moving down</span>
      <span class='position-number'>7</span>
    </td>
    <td class="team-name">
      <a href='http://www.bbc.co.uk/sport/football/teams/manchester-city'>Man City</a>
    </td>
    <td class="played">0</td>

    <td class="home-won">
      <span>0</span>
    </td>
    <td class="home-drawn">0</td>
    <td class="home-lost">0</td>
    <td class="home-for">0</td>
    <td class="home-against">0</td>
    <td class="away-won">
      <span>0</span>
    </td>
    <td class="away-drawn">0</td>
    <td class="away-lost">0</td>
    <td class="away-for">0</td>
    <td class="away-against">0</td>
    <td class="goal-difference">0</td>
    <td class="points">0</td>
    <td class="last-10-games">
      <ol>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="win last" title="Win">
          <span>Win</span>
        </li>
      </ol>
    </td>
    <td class="status">
      <a class="report" href="http://www.bbc.co.uk/sport/0/football/17973148">Report</a>
    </td>
  </tr>
  <tr id="team-137318152" class="team">
    <td class="statistics"></td>
    <td class='position'>
      <span class='moving-down'>Moving down</span>
      <span class='position-number'>8</span>
    </td>
    <td class="team-name">
      <a href='http://www.bbc.co.uk/sport/football/teams/manchester-united'>Man Utd</a>
    </td>
    <td class="played">0</td>

    <td class="home-won">
      <span>0</span>
    </td>
    <td class="home-drawn">0</td>
    <td class="home-lost">0</td>
    <td class="home-for">0</td>
    <td class="home-against">0</td>
    <td class="away-won">
      <span>0</span>
    </td>
    <td class="away-drawn">0</td>
    <td class="away-lost">0</td>
    <td class="away-for">0</td>
    <td class="away-against">0</td>
    <td class="goal-difference">0</td>
    <td class="points">0</td>
    <td class="last-10-games">
      <ol>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="draw" title="Draw">
          <span>Draw</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="loss" title="Loss">
          <span>Loss</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win" title="Win">
          <span>Win</span>
        </li>
        <li class="win last" title="Win">
          <span>Win</span>
        </li>
      </ol>
    </td>
    <td class="status">
      <a class="report" href="http://www.bbc.co.uk/sport/0/football/17973162">Report</a>
    </td>
  </tr>
</tbody>
4

2 回答 2

0

问题是,你的正则表达式太宽泛了。看看你要的是什么:

<tr\b[^>]*>(.*?)manc(.*?)</tr>

让我们稍微简化一下。

<tr>.*?manc.*?</tr>

所以你说,好吧。我需要匹配一个 tr,然后是任何东西,然后是 manc,然后是 ANYTHING,然后是结束 tr。所以。当然会发生的是正则表达式从第一个 tr 开始并且正常。我有一个 tr 让我继续匹配,直到找到 manc。与此同时,你可能刚刚通过了一堆其他的tr。但是你的正则表达式不在乎。

尝试这个:

<tr>(?:(?!</tr>).)*manc.+?</tr>

或者,我猜在你的例子中:

<tr\b[^>]*>(?:(?!</tr>).)*manc.+?</tr>
于 2012-07-02T14:26:49.387 回答
0

REGEX 不适合这种情况,因为它不是为解析器而设计的。除非情况非常宽容,特别是在 JavaScript(它具有相当原始的 REGEX 实现)中,它无法确定哪些开始标签与哪些结束标签匹配。

首先,我们需要使用[\s\S]而不是.因为后者不能多行工作,因为它不匹配空白字符,并且您提到的表格的 HTML 是多行的。前者会,因为它是一个匹配所有空间和非空间的范围 - 即所有东西。

考虑到这一点,您可能很想这样做:

/<tr\b[^>]*?>[\s\S]*?manc[\s\S]*?<\/tr>/gi

...即获取所有提到字符串“manc”的行。

采用以下简化的 HTML:

<table>
    <tr>
        <td>Notts County</td>
    </tr>
    <tr>
        <td>Manchester United</td>
    </tr>
    <tr>
        <td>Arsenal</td>
    </tr>
</table>

...上述模式将匹配

<tr>
    <td>Notts County</td>
</tr>
<tr>
    <td>Manchester United</td>
</tr>

这是合乎逻辑的。REGEX 模式从开头开始,找到开头tr(诺茨县),并询问在不确定数量的可选字符之后是否找到字符串“Manc”。这是。

当然,问题在于,在找到“Manc”时,它不知不觉地越过了tr边界进入下一行,因为我们的[\s\S]*?模式允许它这样做。

我们无法阻止这种情况,因为 REGEX 不允许您否定序列 - 仅允许范围内的字符(除了否定的前瞻和后瞻断言的情况)。

简而言之,无论如何都要学习 REGEX,但你选择了一个很难开始的字符串:)

于 2012-07-02T14:02:16.867 回答