Summing time in DateTime() objects - php

Question

I have an array of DateTime() objects in which I store some time duration (like "H:i")
How can I sum all elements in this array to get total time duration?
And it's also should be taken into account, that if total time duration is grater that 23:59, I have to be able to get nubmer of days.
is this possible?
I was trying to do like this:
$duration = new DateTime('00:00');
foreach($routes as $route) {
$arrival_time = new DateTime();
$arrival_time->setTimestamp($route->arrival_time);
$departure_time = new DateTime();
$departure_time->setTimestamp($route->departure_time);
$leg_duration = $arrival_time->diff($departure_time);
$duration->add($leg_duration);
}
but in $duration I got wrong time.
P.S.
Using $duration->add($leg_duration); I got subtracted from "24:00" time, why?
For example if $leg_duration = new DateTime('02:10'); the result will be "21:50".
$duration->sub($leg_duration); add time to "24:00"
Is this right?

Answer 1

Concerning part of the question: you're using the diff() method in the inverted way, the code should actually be:
$leg_duration = $departure_time->diff($arrival_time);
Because in your code you are calculating $departure_time - $arrival_time (which is negative, thus giving you this "inverted" result).
Concerning the addition of time intervals, as a DateTime object contains a date too, you might have to do something like this to get a meaningful result:
$start = new DateTime('00:00');
$duration = $start;
// ... your loop ...
$total = $start->diff($duration);
$total will be a DateInterval object, whose fields should contain your total time difference (although I didn't test this).

Answer 2

echo sum_the_time('01:45:22', '17:27:03');
this will give you a result:
19:12:2
function sum_the_time($time1, $time2) {
$times = array($time1, $time2);
$seconds = 0;
foreach ($times as $time)
{
list($hour,$minute,$second) = explode(':', $time);
$seconds += $hour*3600;
$seconds += $minute*60;
$seconds += $second;
}
$hours = floor($seconds/3600);
$seconds -= $hours*3600;
$minutes = floor($seconds/60);
$seconds -= $minutes*60;
// return "{$hours}:{$minutes}:{$seconds}";
return sprintf('%02d:%02d:%02d', $hours, $minutes, $seconds); // Thanks to Patrick
}
I found from here