Adding time to a date and time?

[nickburrett]

Hello

I am trying to add 3 hours to a date and time, but when I do I get 3 hours and 12 minutes?

Can anyone explain what I am doing wrong?

PHP Code:

<?

$start_time = "2012-12-11 12:00:00";
$hours_required = "+3 hours";
$finish_calculation = date('Y-m-d h:m:s', strtotime($start_time . "+" . $hours_required));

echo "<br>" . $start_time;
echo "<br>" . $hours_required;
echo "<br>" . $finish_calculation;

?>

[sunfighter]

I have always found working with date time a pain. PHP works in seconds not hours, months, or days. Php calculates the time in seconds from the epochs, January 1 1970 00:00:00 GMT, and goes from there.

Your answer, but you should look up why this works:

PHP Code:

<?php
$start_time = new DateTime('2012-12-11 12:00:00');
echo $start_time->format('Y-m-d H:i:s') . "<br />";

$finish_calculation = $start_time->add(new DateInterval('PT3H'));
echo $finish_calculation->format('Y-m-d H:i:s') . "<br />";
?>

P.S. FYI you should always start php with <?php and not <?. The later has been discontinued and it will eventually bite you.

[kbluhm]

http://www.php.net/date

Lowercase m is the numeric month with leading zeros (12 == December)

Replace the lowercase m with a lowercase i... which is minutes with leading zeros.

strtotime() also takes a second argument, the start time, which always defaults to the current timestamp... so this will also work:

PHP Code:

$start_time = "2012-12-11 12:00:00"; 
$hours_required = "+3 hours"; 

$finish_calculation = date( 'Y-m-d h:i:s', strtotime(
    $hours_required,
    strtotime( $start_time )
) ); 


[Fou-Lu]

Datetime ftw (5.3+):

PHP Code:

$dt = new DateTime($start_time);
$dt->add(new DateInterval('PT3H'));
print $dt->format('Y-m-d h:i:s'); 


As for PHP time being an integer, I'm not sure how many languages *don't* use integers to store time (including things like filesystem inodes). This is part of the issue with the year 2038 time problem. Of course by 2038 this won't be an issue as x86 will be a thing of the past.