date math

jphilapy

Hi,

I am trying to utilize the strtotime function but am getting unexpected results. I created the following function to return the difference between two dates.

function showDateDiff($date1, $date2)
{     

    $ndate1 = strtotime($date1);
    $ndate2 = strtotime($date2);

$date_diff = $ndate2 - $ndate1;

return $date_diff;
}


print showDateDiff("03/22/2006","04/21/2006");

The above code will return 2588400 (seconds in 30 days)

3/22/2006 to 04/21/2006 is exactly 31 days however if you multiply 86400 (seconds in a day) by 30 you get 2592000. I would expect that the two answers should be the same.

Not sure what I am doing wrong.

Thanks,
Jeff

rincewind456

Nothing wrong that I can see, there are 30 days between those two dates not 31.
By your logic there would be 2 days between

print showDateDiff("03/22/2006","03/23/2006");

but there is only one.

Installer

The 3600 second difference (1 hour) is due to the lost hour due to daylight saving time taking effect in between in your locale.

jphilapy

Installer wrote:
The 3600 second difference (1 hour) is due to the lost hour due to daylight saving time taking effect in between in your locale.

Thanks for your reply. How do I get around this difference?

I'm using php 4.1

Jeff

jphilapy

rincewind456 wrote:
Nothing wrong that I can see, there are 30 days between those two dates not 31.
By your logic there would be 2 days between
print showDateDiff("03/22/2006","03/23/2006");
but there is only one.

Ooops in my first post I meant to say 30. it was a typo.

Installer

If you want to get the "normal" amount of time (that is, as if DST didn't exist), change your function to this:

function showDateDiff($date1, $date2)
{     

    $ndate1 = strtotime($date1 . 'GMT');
    $ndate2 = strtotime($date2 . 'GMT');

$date_diff = $ndate2 - $ndate1;

return $date_diff;
}

jphilapy

Installer wrote:
If you want to get the "normal" amount of time (that is, as if DST didn't exist), change your function to this:
function showDateDiff($date1, $date2)
{     

    $ndate1 = strtotime($date1 . 'GMT');
    $ndate2 = strtotime($date2 . 'GMT');

$date_diff = $ndate2 - $ndate1;

return $date_diff;
}

Thanks it fixed my problem.

Jeff