- array_reverse: documentation ( source)
- print_r: documentation ( source)
<?php
$start = (new DateTime('1 year ago'))->modify('first day of this month');
$end = (new DateTime())->modify('first day of this month');
$interval = new DateInterval('P1M');
$period = new DatePeriod($start, $interval, $end);
$months = array();
foreach ($period as $dt) {
$months[$dt->format('Y-m-d')] = $dt->format('Y-m');
}
$reverse_months = array_reverse($months);
print_r($reverse_months);