- var_dump: documentation ( source)
<?php
$input = new \DateTime('2017-07-16');
$firstDayOfMonth = new \DateTime($input->format('Y-m-01'));
$order = (int)($input->format('n') / 7) + 1;
if (($input->format('N') % 7) <= ($firstDayOfMonth->format('N') % 7))
$order++;
var_dump($input->format('l'));
var_dump($order);