Problem with comparing 2 Dates

kumschick

Hi,

I would like to compare to dates

ie: 20050422 - 20050331 = 91 (math)
but if you say that this value is a date the result should be 40.

And that's my problem, I don't know how to calcule with dates.

I did it this way:

$test = date1 - date2;
echo $test;

but it's normal that it doesn't work! 🙂

May someone help me, thx

LordShryku

[man]strtotime[/man] both of them. Subtract. Multiply the result by 86400 (1 day in seconds). [man]floor[/man], [man]ceil[/man], or [man]round[/man] the results.

paulnaj

Hi kumschick,

Read the manual ... date/time functions 😉

Paul.

kumschick

ah yes! now I remember it's strtotime
but there is a problem with this function till version 5.0.2

and on the server is currently version 5.0.1! 🙁

isn't there an other way?

Alain

LordShryku

Uhm....what problem?

kumschick

In PHP 5 up to 5.0.2, "now" and other relative times are wrongly computed from today's midnight. It differs from other versions where it is correctly computed from current time.

paulnaj

Originally posted by paulnaj
Read the manual ... date/time functions 😉

I refer you to a reply I made some time ago!

kumschick

yes thx but it doesn't help me when tell me to read the manual date / time! i know that already! 🙂

i'm now trying to fix the problem with mktime, but i'm also stuck!

$exp_date_left = date("d.m.Y", mktime(0, 0, 0, date("m"), date("d")-22, date("Y")));

it doesn't work as espected. I want to know how many days are left till expiration!

Alain

paulnaj

Hi kumschick,

The thing is, is that the answer is there, so it should help you, but sorry for being sarcastic 🙁

I don't use PHP5 so can't absolutely sure but the warning about PHP 5 suggests that you will only have a problem if you need to consider the time as well as the date.

Paul 🙂

mrhappiness

Originally posted by kumschick
In PHP 5 up to 5.0.2, "now" and other relative times are wrongly computed from today's midnight. It differs from other versions where it is correctly computed from current time.

Bt if you want to subtract dates it doesn't matter because both dates are strtotime'd the same (wrong) way and so you don't caclulate

strtotime of date 1 - strtotime of date 2

but

(strtotime of date 1 + some error value) - (strtotime of date 2 + same error value)

kumschick

i tried it with strtotime but I get strange stuff !?!?!?!?!

$mydate1 = "2010-01-01"; // SOME_DATE
$mydate2 = "2005-04-16"; // TODAY


$test = strtotime("$mydate1") - strtotime("$mydate2");
echo"$test";

and the resolt was:
2010-01-01 - 2005-04-16 = 148698000

paulnaj

Hi,

A timestamp is just a large integer representing the number of secs after some baseline date. But what you want is the number of days. So, divide by the number of seconds in a day.

Then calculate the difference ...

<?php 
define('SECONDS_IN_A_DAY', 86400); // 60*60*24

$mydate1 = "2010-01-01"; // SOME_DATE 
$mydate2 = "2005-04-16"; // TODAY 

$mydays1 = floor(strtotime($mydate1)/SECONDS_IN_A_DAY);
echo '<br> d1 = '.$mydays1.' days.';
$mydays2 = floor(strtotime($mydate2)/SECONDS_IN_A_DAY);
echo '<br> d2 = '.$mydays2.' days.';

echo '<br> d1 - d2 = '.($mydays1 - $mydays2).' days.';
?>

Paul 🙂

kumschick

cool!
thx mate