php DateTime diff method behavior

Question

I have to find the days until an expiration date. I tried to use diff method of DateTime class.

$dataexp = 2013-11-06 00:00:00 ;
$now = 2013-11-05 13:00:00 ;

$dtn = new DateTime('now');
$dte = new DateTime($dataexp);

$diff = $dtn->diff($dte);

$days = sprintf("%01d", $diff->days);

$days ---> display 1

My problem is if the dataexp is in the past of 1 day the result of diff is 1 and not -1

$dataexp = 2013-11-04 00:00:00 ;
$now = 2013-11-05 13:00:00 ;

$dtn = new DateTime('now');
$dte = new DateTime($dataexp);

$days = sprintf("%01d", $diff->days);

$days ---> display 1

What method could I use to get what I want? (-1 days)? Thanks

`diff` needs formatting to show the proper value. #Look at the examples in the manual. http://php.net/manual/en/datetime.diff.php — Pekka, Nov 05 '13 at 14:42
"`display 1`" - what does that mean exactly? The code you show displays nothing. — deceze, Nov 05 '13 at 14:45

score 2 · Accepted Answer · answered Nov 05 '13 at 14:45

2

See DateInterval::format(), specifically the r format character.

echo $diff->format('%r%d');

answered Nov 05 '13 at 14:45

John Conde

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It works, but if $dataexp = 2013-11-05 12:00:00 $diff->format('%r%d') display -0 – Paolo Rossi Nov 05 '13 at 14:53
That's because of your time values. I'd remove them before doing your date math. – John Conde Nov 05 '13 at 14:54
Can I remove the time of my date with DateTime class? – Paolo Rossi Nov 05 '13 at 15:00
I *think* using something like `$dtn->modify('midnight')` will work but that's just a guess and untested. If you're getting your values from a DB you can remove them in your query. If you use MySQL you can use the `DATE()` function to trim the time values. – John Conde Nov 05 '13 at 15:02
mmm I 've a problem if my $dataexpp = 2014-02-03 00:00:00, $diff->format('%r%d') display 28. Why?? – Paolo Rossi Nov 05 '13 at 15:12
That's because `%d` will only show up to 31 days. After that you need to start using other flags like `%m` for months, too. – John Conde Nov 05 '13 at 15:22
Ok, but if I display only the days? it is possible? I must display -1 or 1 or 20 or 60 days. – Paolo Rossi Nov 05 '13 at 15:33
Try using `$diff->r` with `$diff->days` – John Conde Nov 05 '13 at 15:45

php DateTime diff method behavior

1 Answers1