<?php
/**
in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] ) : bool
*/
$os = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $os)) {
echo "Got Irix";
}
if (in_array("mac", $os)) {
echo "Got mac";
}
?>
if (!empty($data_days) && in_array(1, $data_days, true)){ // use numeric value 1, not string