In PHP, what are the recommended methods for parsing and extracting specific information from HTML content retrieved from external sources for analysis purposes?

When parsing and extracting specific information from HTML content retrieved from external sources in PHP, the recommended method is to use a library like DOMDocument or Simple HTML DOM Parser. These libraries provide functions to navigate the HTML structure and extract the desired data using CSS selectors or XPath queries. By using these libraries, you can easily retrieve and analyze specific information from the HTML content without having to manually parse the raw HTML.

// Example using DOMDocument to extract specific information from HTML content

// HTML content retrieved from external source
$htmlContent = file_get_contents('https://example.com');

// Create a new DOMDocument object
$dom = new DOMDocument();

// Load the HTML content into the DOMDocument
$dom->loadHTML($htmlContent);

// Use XPath to query specific elements in the HTML content
$xpath = new DOMXPath($dom);
$elements = $xpath->query('//div[@class="content"]');

// Loop through the matched elements and extract the desired information
foreach ($elements as $element) {
    echo $element->nodeValue . "\n";
}