get HashTag

hashtag.php

<?php
function convertAll($str) {
    $regex = "/[@#](\w+)/";

    $hrefs = [
        '#' =&gt; 'hashtag?tag',
        '@' =&gt; 'profile?username'
    ];
    
    $result = preg_replace_callback($regex, function($matches) use ($hrefs) {
         return sprintf(
             '&lt;a href="%s=%s"&gt;%s&lt;/a&gt;',
             $hrefs[$matches[0][0]],
             $matches[1], 
             $matches[0]
         );
    }, $str);
        
    return($result);
}