- var_dump: documentation ( source)
<?php
$input = new \DateTime('2017-07-17');
$firstDayOfMonth = new \DateTime($input->format('Y-m-01'));
$order = (int)($input->format('n') / 7) + 1;
if ($input->format('N') > $firstDayOfMonth->format('N'))
$order++;
var_dump($input->format('l'));
var_dump($order);