DateTime::setTimezone
Note that the sub() and add() methods will modify the value of the object you're calling the method on! This is very untypical for a method that returns a value of its own type. You could misunderstand it that the method would return a new instance with the modified value, but in fact it modifies itself! This is undocumented here. (Only a side note on procedural style mentions it, but it obviously does not apply to object oriented style.)
DateTime::sub
date_sub
(PHP 5 >= 5.3.0)
DateTime::sub -- date_sub — Soustrait une durée à un objet DateTime
Description
Style orienté objet
Style procédural
Soustrait la durée spécifiée par l'objet DateInterval de l'objet DateTime.
Liste de paramètres
- object
-
Style procédural uniquement : Un objet DateTime retourné par la fonction date_create(). Cette fonction modifie cet objet.
- interval
-
Un objet DateInterval
Valeurs de retour
Retourne l'objet DateTime pour chainer les méthodes ou FALSE si une erreur survient.
Exemples
Exemple #1 Exemple avec DateTime::sub()
Style orienté objet
<?php
$date = new DateTime('2000-01-20');
$date->sub(new DateInterval('P10D'));
echo $date->format('Y-m-d') . "\n";
?>
Style procédural
<?php
$date = date_create('2000-01-20');
date_sub($date, date_interval_create_from_date_string('10 days'));
echo date_format($date, 'Y-m-d');
?>
Les exemples ci-dessus vont afficher :
2000-01-10
Exemple #2 Autres exemples avec DateTime::sub()
<?php
$date = new DateTime('2000-01-20');
$date->sub(new DateInterval('PT10H30S'));
echo $date->format('Y-m-d H:i:s') . "\n";
$date = new DateTime('2000-01-20');
$date->sub(new DateInterval('P7Y5M4DT4H3M2S'));
echo $date->format('Y-m-d H:i:s') . "\n";
?>
L'exemple ci-dessus va afficher :
2000-01-19 13:59:30 1992-08-15 19:56:58
Exemple #3 Attention à la soustraction de mois
<?php
$date = new DateTime('2001-04-30');
$interval = new DateInterval('P1M');
$date->sub($interval);
echo $date->format('Y-m-d') . "\n";
$date->sub($interval);
echo $date->format('Y-m-d') . "\n";
?>
L'exemple ci-dessus va afficher :
2001-03-30 2001-03-02
Notes
DateTime::modify() est une alternative à utiliser avec PHP 5.2.
Voir aussi
- DateTime::add() - Ajoute une durée à un objet DateTime
- DateTime::diff() - Retourne la différence entre deux objets DateTime
- DateTime::modify() - Modifie le timestamp
add a note
User Contributed Notes
DateTime::sub
Anonymous
01-Feb-2011 07:15
php at keith tyler dot com
30-Nov-2010 11:53
If you use diff() after sub(), the effects of the sub() will be repeated on the date object.
It doesn't matter if the object is the one diffed or doing the diffing (i.e. which object you call diff() from).
<?php
$today = new DateTime();
$newdate = new DateTime();
print_r($newdate);
$newdate->sub(new DateInterval("PT1S"));
print_r($newdate);
$s = $newdate->diff($today);
print_r($newdate);
$s = $today->diff($newdate);
print_r($newdate);
$s = $today->diff($newdate);
print_r($newdate);
?>
Prints:
DateTime Object
(
[date] => 2010-11-30 18:43:48
[timezone_type] => 3
[timezone] => America/Los_Angeles
)
DateTime Object
(
[date] => 2010-11-30 18:43:47
[timezone_type] => 3
[timezone] => America/Los_Angeles
)
DateTime Object
(
[date] => 2010-11-30 18:43:46
[timezone_type] => 3
[timezone] => America/Los_Angeles
)
DateTime Object
(
[date] => 2010-11-30 18:43:45
[timezone_type] => 3
[timezone] => America/Los_Angeles
)
DateTime Object
(
[date] => 2010-11-30 18:43:44
[timezone_type] => 3
[timezone] => America/Los_Angeles
)
Note that using add() instead of sub() does NOT have the same effect.
This is particularly undesirable -- in this example you make a datetime, use sub() to make it a relative time in the past, and then date->diff() to confirm the difference. But the diff() inadvertendly makes the difference 2x.