doucang6739 2018-08-16 20:11
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通过xpath中的子li节点进行迭代

I have the following HTML:

$page = '<html>
<head>
<title>Page</title>
</head>

<body>

<div>
    <div>
        <div>
        </div>
        <div class="this one">
            <h2>Ignore</h2>
            <p>Text</p>

            <h2>Header 1</h2>
            <ul><li>List Value 1</li></ul>

            <h2>Header 2</h2>
            <ul><li>List Value 2</li></ul>

            <h2>Ignore</h2>
            <ul><li>List Value 3</li></ul>

            <h2>Header 3</h2>
            <ul>
                <li>List Value A</li>
                <li>List Value B</li>
                <li>List Value C</li>
            </ul>

            <h2>Ignore</h2>
            <p>Text</p>
        </div>
    </div>
</div>

</body>
</html>';

I am trying to get the li list for Header 3 only and the following code doesn't work;

$doc->loadHTML($page);   
$xpath = new DomXPath($doc);

$nodes = $xpath->query("//div[@class='this one']/h2[.='Header 3']/ul/li");
foreach($nodes as $node) { 
    echo $node->nodeValue . "<br />";
}

I am expecting the output:

List Value A<br />
List Value B<br />
List Value C<br />
  • 写回答

1条回答 默认 最新

  • dtz46697 2018-08-16 20:19
    关注

    This is the expression that you want:

    //div[@class = 'this one']/h2[text() = 'Header 3']/following-sibling::ul[1]/li
    

    Broken down a bit:

    • //div[@class = 'this one'] - Match all <div>s in the document with the specified class attribute value

    • …/h2[text() = 'Header 3'] - Match all <h2>s that are children of those <div>s that have the specified text content

    • …/following-sibling::ul - Use the following-sibling axis to match <ul>s that appear after the <h2>s

    • …[1] - Match only the first <ul> that is a sibling of the matched <h2> (… remembering that indexes are 1-based in XPath expressions)

    • …/li - And match all of the <li>s which are children of that <ul>

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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