$re = '/(?i)\b((?:https?://|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}/)(?:[^\s($)<>]+|\(([^\s()<>]+|(\([^\s( )<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s($r)<>]+\)))*\)|[^\s`!()\[\]{};:\'\".,<>?«»“”‘’]))/m';
$str = 'https://www.linkedin.com/in/amalia-
daniela-nicolaita-78021870';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php