How can I efficiently extract specific text from HTML using PHP DOMDocument and DOMXpath?-PHP Tutorial-php.cn

How can I efficiently extract specific text from HTML using PHP DOMDocument and DOMXpath?

Susan Sarandon

Release： 2024-10-31 01:18:29

Original

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How can I efficiently extract specific text from HTML using PHP DOMDocument and DOMXpath?

Parsing HTML with PHP DOMDocument

Utilizing the DOMDocument class in PHP provides a more efficient and reliable method for parsing HTML compared to using regular expressions. To extract specific text from an HTML document, the DOMXpath class plays a crucial role.

Example:

Consider the following HTML string:

<code class="html"><div class="main">
    <div class="text">
        Capture this text 1
    </div>
</div>

<div class="main">
    <div class="text">
        Capture this text 2
    </div>
</div></code>

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Our goal is to retrieve the text "Capture this text 1" and "Capture this text 2."

XPath Query Approach:

Instead of relying on DOMDocument::getElementsByTagName, which retrieves all tags with a given name, XPath allows us to target specific elements based on their structure.

<code class="php">$html = <<<HTML
<div class="main">
    <div class="text">
        Capture this text 1
    </div>
</div>

<div class="main">
    <div class="text">
        Capture this text 2
    </div>
</div>
HTML;

$dom = new DOMDocument();
$dom->loadHTML($html);

$xpath = new DOMXPath($dom);</code>

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Using XPath, we can execute the following query:

<code class="php">$tags = $xpath->query('//div[@class="main"]/div[@class="text"]');
foreach ($tags as $tag) {
    var_dump(trim($tag->nodeValue));
}</code>

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This query retrieves all div tags with the class "text" that are nested within div tags with the class "main."

Output:

string 'Capture this text 1' (length=19)
string 'Capture this text 2' (length=19)

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This demonstrates the effectiveness of using PHP's DOMDocument and DOMXpath for accurate HTML parsing and extraction of specific content.

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