PHP version of jQuery's grep

<?php
 
function grep(Array $elems, Closure $callback, $inv = false) {
 
    $ret = array();
    $retVal;
    $inv = !!$inv;
 
    for ($i = 0, $length = count($elems); $i < $length; $i++) {
        $retVal = call_user_func($callback, $elems[$i], $i);
        if ($inv !== $retVal) {
            $ret[] = $elems[$i];
        }
    }
 
    return $ret;
 
}
 
$arr = array(1, 9, 3, 8, 6, 1, 5, 9, 4, 7, 3, 8, 6, 9, 1);
 
print_r($arr);
// 1, 9, 3, 8, 6, 1, 5, 9, 4, 7, 3, 8, 6, 9, 1
 
$arr = grep($arr, function($n, $i) {
    return ($n != 5 && $i > 4);
});
 
print_r($arr);
// 1, 9, 4, 7, 3, 8, 6, 9, 1