PHP 7.1.20 Released

DateTime::setTimezone

date_timezone_set

(PHP 5 >= 5.2.0, PHP 7)

DateTime::setTimezone -- date_timezone_setDateTime オブジェクトのタイムゾーンを設定する

説明

オブジェクト指向型

public DateTime DateTime::setTimezone ( DateTimeZone $timezone )

手続き型

新しいタイムゾーンを DateTime オブジェクトに設定します。

パラメータ

object

手続き型のみ: date_create() が返す DateTime オブジェクト。 この関数は、このオブジェクトを変更します。

timezone

指定したいタイムゾーンを表す DateTimeZone オブジェクト。

返り値

メソッドチェインに使う DateTime オブジェクトを返します。失敗した場合に FALSE を返します。

変更履歴

バージョン 説明
5.3.0成功した場合の返り値が NULL から DateTime に変更されました。

例1 DateTime::setTimeZone() の例

オブジェクト指向型

<?php
$date 
= new DateTime('2000-01-01', new DateTimeZone('Pacific/Nauru'));
echo 
$date->format('Y-m-d H:i:sP') . "\n";

$date->setTimezone(new DateTimeZone('Pacific/Chatham'));
echo 
$date->format('Y-m-d H:i:sP') . "\n";
?>

手続き型

<?php
$date 
date_create('2000-01-01'timezone_open('Pacific/Nauru'));
echo 
date_format($date'Y-m-d H:i:sP') . "\n";

date_timezone_set($datetimezone_open('Pacific/Chatham'));
echo 
date_format($date'Y-m-d H:i:sP') . "\n";
?>

上の例の出力は以下となります。

2000-01-01 00:00:00+12:00
2000-01-01 01:45:00+13:45

参考

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User Contributed Notes 6 notes

up
37
jamsilver at gmail dot com
3 years ago
In response to the other comments expressing surprise that changing the timezone does not affect the timestamp:

A UNIX timestamp is defined as the number of seconds that have elapsed since 00:00:00 (UTC), Thursday, 1 January 1970.

So: with respect to UTC. Always.

Calling setTimezone() never changes the actual "absolute", underlying, moment-in-time itself. It only changes the timezone you wish to "view" that moment "from". Consider the following:

<?php
// A time in London.
$datetime = new DateTime('2015-06-22T10:40:25', new DateTimeZone('Europe/London'));

// I wonder how that SAME moment-in-time would
// be described in other places around the world.
$datetime->setTimezone(new DateTimeZone('Australia/Sydney'));
print
$datetime->format('Y-m-d H:i:s (e)');
 
// 2015-06-22 19:40:25 (Australia/Sydney)

$datetime->setTimezone(new DateTimeZone('America/New_York'));
print
$datetime->format('Y-m-d H:i:s (e)');
 
// 2015-06-22 05:40:25 (America/New_York)

$datetime->setTimezone(new DateTimeZone('Asia/Calcutta'));
print
$datetime->format('Y-m-d H:i:s (e)');
 
// 2015-06-22 15:10:25 (Asia/Calcutta)
?>

Please note that ALL of these date strings unambiguously represent the exact same moment-in-time. Therefore, calling getTimestamp() at any stage will return the same result:

<?php
$datetime
->getTimestamp();
 
// 1434966025
?>
up
3
Alex
1 year ago
Surprising that the timezone works only specified in the separated method in case if you'll use ->format('U').

this does NOT apply timezone +0200 in the $timestamp:

<?php
    $date
= new \DateTime(strtotime(time()), new DateTimeZone(system('date +%z')));
   
$timestamp = $date->format('U');
?>

this will apply timezone +0200 in the $timestamp:

<?php
    $date
= new \DateTime(strtotime(time()));
   
$date->setTimezone(new DateTimeZone(system('date +%z')));
   
$timestamp = $date->format('U');
?>
up
6
keithm at aoeex dot com
8 years ago
The timestamp value represented by the DateTime object is not modified when you set the timezone using this method.  Only the timezone, and thus the resulting display formatting, is affected.

This can be seen using the following test code:
<?php
$MNTTZ
= new DateTimeZone('America/Denver');
$ESTTZ = new DateTimeZone('America/New_York');

$dt = new DateTime('11/24/2009 2:00 pm', $MNTTZ);
var_dump($dt->format(DATE_RFC822), $dt->format('U'));
$dt->setTimezone($ESTTZ);
var_dump($dt->format(DATE_RFC822), $dt->format('U'));

/** Output:
string(29) "Tue, 24 Nov 09 14:00:00 -0700"
string(10) "1259096400"
string(29) "Tue, 24 Nov 09 16:00:00 -0500"
string(10) "1259096400"
**/
?>

As such, you can use this to easily convert between timezones for display purposes.
up
1
balbuf
2 years ago
It appears that what forzi at mail333 dot com said is correct.

When you reset the timezone on a DateTime object using a timezone that was instantiated with a GMT offset (e.g. <?php new DateTimeZone('-0500'); ?>) the timestamp as reported by <?php $dt->format('U'); ?> changes.

However, the value reported by <?php $dt->getTimestamp(); ?> does _not_ change. Interestingly, once <?php $dt->getTimestamp(); is called, the value from <?php $dt->format('U'); ?> starts returning the correct timestamp. This appears to be a bug.

In any case, other output values from format() seem to be accurate, and the true timestamp is always accessible via getTimestamp().
up
-1
salladin
6 years ago
I found unexpected behaviour when passing a timestamp.
timezone seems to always be GMT+0000 unless setTimezone() is set.

<?php

$MNTTZ
= new DateTimeZone('America/Denver');
$ts = 1336476757;

$dt = new DateTime("@$ts", $MNTTZ);
var_dump($dt->format('T'), $dt->format('U'));

$dt->setTimezone($MNTTZ);
var_dump($dt->format('T'), $dt->format('U'));

/** Output:
string(8) "GMT+0000"
string(10) "1336476757"
string(3) "MDT"
string(10) "1336476757"
**/

?>
up
-1
forzi at mail333 dot com
3 years ago
<?php
$MNTTZ
= new DateTimeZone('America/Denver');
$ESTTZ = new DateTimeZone('America/New_York');

$dt = new DateTime('11/24/2009 2:00 pm', $MNTTZ);
var_dump($dt->format(DATE_RFC822), $dt->format('U'));
$dt->setTimezone($ESTTZ);
var_dump($dt->format(DATE_RFC822), $dt->format('U'));
?>
doesn't changes timestamp
But
<?php
$MNTTZ
= new DateTimeZone('America/Denver');
$ESTTZ = new DateTimeZone('-0500');

$dt = new DateTime('11/24/2009 2:00 pm', $MNTTZ);
var_dump($dt->format(DATE_RFC822), $dt->format('U'));
$dt->setTimezone($ESTTZ);
var_dump($dt->format(DATE_RFC822), $dt->format('U'));
?>
changes timestamp

It is possible to fix that by:
<?php
$timestamp
= $date->getTimestamp();
$date->setTimezone($value);
$date->setTimestamp($timestamp);
?>
But WTF???
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