What is the best approach to adding a blacklist to prevent certain URLs from being replaced in PHP?

To add a blacklist to prevent certain URLs from being replaced in PHP, you can create an array of URLs that you want to blacklist. Then, when replacing URLs in a string, you can check if the URL is in the blacklist array before replacing it. 

// Blacklist of URLs to prevent from being replaced
$blacklist = array("example.com", "test.com");

// String with URLs to replace
$string = "Visit example.com for more information. Also check out test.com for updates.";

// Replace URLs, but skip those in the blacklist
foreach($blacklist as $url) {
    $string = preg_replace("/\b$url\b/i", $url, $string);
}

echo $string;

Keywords

PHP blacklist URL prevention replace

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