PHP: DatePeriod with last day of month - php

Question

I'd like to work with PHP DateInterval to iterate through months:
$from = new DateTime();
$from->setDate(2014, 1, 31);
$period = new DatePeriod($from, new DateInterval('P1M'), 12);
I'd expect it to returns 31 January, 28 February (as the DateInterval is 1 month), but it actually returns 31 January, 3 March, 3 of April... hence skipping February.
Is there any way to do this simply?
Thanks!
EDIT : as a refernece, here is a solution that seems to cover most use cases:
$date = new DateTime('2014-01-31');
$start = $date->format('n');
for ($i = 0; $i < 28; $i++) {
$current = clone $date;
$current->modify('+'.$i.' month');
if ($current->format('n') > ($start % 12) && $start !== 12) {
$current->modify('last day of last month');
}
$start++;
echo $current->format('Y-m-d').PHP_EOL;
}

Answer 1

You can use DateTime::modify():
$date = new DateTime('last day of january');
echo $date->format('Y-m-d').PHP_EOL;
for ($i = 1; $i < 12; $i++) {
$date->modify('last day of next month');
echo $date->format('Y-m-d').PHP_EOL;
}
EDIT: I think I didn't understand your question clearly. Here is a new version:
$date = new DateTime('2014-01-31');
for ($i = 0; $i < 12; $i++) {
$current = clone $date;
$current->modify('+'.$i.' month');
if ($current->format('n') > $i + 1) {
$current->modify('last day of last month');
}
echo $current->format('Y-m-d').PHP_EOL;
}

Answer 2

The issue is cause by the variance between the last day in each of the months within the range. ie. February ending on 28 instead of 31 and the addition of 1 month from the last day 2014-01-31 + 1 month = 2014-03-03 https://3v4l.org/Y42QJ
To resolve the issue with DatePeriod and simplify it a bit, adjust the initial date by resetting the specified date to the first day of the specified month, by using first day of this month.
Then during iteration, you can modify the date period date by using last day of this month to retrieve the bounds of the currently iterated month.
Example: https://3v4l.org/889mB
$from = new DateTime('2014-01-31');
$from->modify('first day of this month'); //2014-01-01
$period = new DatePeriod($from, new DateInterval('P1M'), 12);
foreach ($period as $date) {
echo $date->modify('last day of this month')->format('Y-m-d');
}
Result:
2014-01-31
2014-02-28
2014-03-31
2014-04-30
2014-05-31
2014-06-30
2014-07-31
2014-08-31
2014-09-30
2014-10-31
2014-11-30
2014-12-31
2015-01-31
Then to expand on this approach, in order to retrieve the desired day from the specified date, such as the 29th. You can extract the specified day and adjust the currently iterated month as needed when the day is out of bounds for that month.
Example: https://3v4l.org/SlEJc
$from = new DateTime('2014-01-29');
$day = $from->format('j');
$from->modify('first day of this month'); //2014-01-01
$period = new DatePeriod($from, new DateInterval('P1M'), 12);
foreach ($period as $date) {
$lastDay = clone $date;
$lastDay->modify('last day of this month');
$date->setDate($date->format('Y'), $date->format('n'), $day);
if ($date > $lastDay) {
$date = $lastDay;
}
echo $date->format('Y-m-d');
}
Result:
2014-01-29
2014-02-28 #notice the last day of february is used
2014-03-29
2014-04-29
2014-05-29
2014-06-29
2014-07-29
2014-08-29
2014-09-29
2014-10-29
2014-11-29
2014-12-29
2015-01-29

Answer 3

You may try like this:
$date = new DateTime();
$lastDayOfMonth = $date->modify(
sprintf('+%d days', $date->format('t') - $date->format('j'))
);

Answer 4

I would do it probably like this
$max = array (
31,28,31,30,31,30,31,31,30,31,30,31
); //days in month
$month = 1;
$year = 2014;
$day = 31;
$iterate = 12;
$dates = array();
for ($i = 0;$i < $iterate;$i++) {
$tmp_month = ($month + $i) % 12;
$tmp_year = $year + floor($month+$i)/12;
$tmp_day = min($day, $max[$tmp_month]);
$tmp = new DateTime();
$tmp->setDate($tmp_year, $tmp_month + 1, $tmp_day);
$dates[] = $tmp;
}
var_dump($dates);
This keeps to the same day each month if possible