PHP: print all days between a given day and end of month - php

Question

I don't want to return DATE (Y-m-d).
I need to print all days until end of month from a given day independently of the month or year.
I tried both [$array as $i] - [$array as $key] and didn't work.
$myday (for example = 19)
return $days
would result:
Array
[0] => 20
[1] => 21
[2] => 22
[3] => 23
...
[31] => 31 || [30] => 30 || [28] => 28
I would need each value for $days to compare each to another field.
Didn't try to use $myday as regular number instead of treating as date. And not use strtotime, mktime....
EDITING
Need something very simple like this one:
$output = array();
for ($i=$myday+1;$i<=31 || $i<=30 || $i<=28;$i++) {
$output[] = $i;
}
But print_r won't do it, I need to return as each value to use in different if conditions

Answer 1

This is easily done using DateTime(), DateInterval(), DatePeriod(), and relative date formats.
$start = (new DateTime())->setDate(date('Y'), date('m'), $myday + 1);
$end = new DateTime('first day of next month');
$interval = new DateInterval('P1D');
$period = new DatePeriod($start, $interval, $end);
$days = array();
foreach($period as $date) {
$days[] = $date->format('d');
}
Results
Array
(
[0] => 20
[1] => 21
[2] => 22
[3] => 23
[4] => 24
[5] => 25
[6] => 26
[7] => 27
[8] => 28
[9] => 29
[10] => 30
[11] => 31
)
Demo