(PHP 5 >= 5.2.0, PHP 7, PHP 8)
DateTime::__construct — Gibt ein neues DateTime-Objekt zurück
Wie DateTimeImmutable::__construct(), verwendet aber DateTime. Es sollte in Betracht gezogen werden, die Klasse DateTimeImmutable und deren Features zu verwenden.
Gibt ein neues DateTime-Objekt zurück.
datetimeEin Datums/Zeit Zeichenkette. Gültige Formate werden unter Datums- und Zeitformate erläutert.
Wird "now" übergeben, so wird die aktuelle Uhrzeit verwendet,
wenn $timezone übergeben wird.
timezone
Ein DateTimeZone-Objekt, welches die Zeitzone
von $datetime repräsentiert.
Wenn $timezone nicht übergeben wird oder null
ist, wird die aktuelle Zeitzone verwendet.
Hinweis:
Der Parameter
$timezoneund die aktuelle Zeitzone werden ignoriert, wenn der Parameter$datetimeentweder ein UNIX-Zeitstempel ist (z.B:@946684800), oder wenn in ihm eine Zeitzone spezifiziert wird (z.B:2010-01-28T15:00:00+02:00).
Gibt eine neue Instanz von DateTime zurück.
Prozeduraler Stil Im Fehlerfall wird false zurückgegeben.
There's a reason for ignoring the time zone when you pass a timestamp to __construct. That is, UNIX timestamps are by definition based on UTC. @1234567890 represents the same date/time regardless of time zone. So there's no need for a time zone at all.
The theoretical limits of the date range seem to be "-9999-01-01" through "9999-12-31" (PHP 5.2.9 on Windows Vista 64):
<?php
$d = new DateTime("9999-12-31");
$d->format("Y-m-d"); // "9999-12-31"
$d = new DateTime("0000-12-31");
$d->format("Y-m-d"); // "0000-12-31"
$d = new DateTime("-9999-12-31");
$d->format("Y-m-d"); // "-9999-12-31"
?>
Dates above 10000 and below -10000 do not throw errors but produce weird results:
<?php
$d = new DateTime("10019-01-01");
$d->format("Y-m-d"); // "2009-01-01"
$d = new DateTime("10009-01-01");
$d->format("Y-m-d"); // "2009-01-01"
$d = new DateTime("-10019-01-01");
$d->format("Y-m-d"); // "2009-01-01"
?>
Note that the DateTime ctor also accepts boolean false and empty strings, and treats them the same as NULL (i.e. result is current date and time). This may lead to unexpected results if you forward function return values without explicitly checking them first.
Empty arrays and boolean true trigger PHP warnings OTOH.
(checked with PHP 5.5.18)
A definite "gotcha" (while documented) that exists in the __construct is that it ignores your timezone if the $time is a timestamp. While this may not make sense, the object does provide you with methods to work around it.
<?php
// New Timezone Object
$timezone = new DateTimeZone('America/New_York');
// New DateTime Object
$date = new DateTime('@1306123200', $timezone);
// You would expect the date to be 2011-05-23 00:00:00
// But it actually outputs 2011-05-23 04:00:00
echo $date->format('Y-m-d H:i:s');
// You can still set the timezone though like so...
$date->setTimezone($timezone);
// This will now output 2011-05-23 00:00:00
echo $date->format('Y-m-d H:i:s');
?>
It is worth noting:
If you have not setup a default timezone, an Exception (or error if PHP < 5.3.0) will be thrown even when the $time parameter of the constructor includes a timezone or is a UNIX timestamp.
At least for me, this was unexpected considering that the $timezone parameter is ignored in the cases when "the $time parameter either is a UNIX timestamp (e.g. @946684800) or specifies a timezone (e.g. 2010-01-28T15:00:00+02:00)."
If time cannot be parsed an exception of type Exception is thrown which can be caught, however an E_WARNING is emitted as well. This might be confusing if you are converting warnings to exceptions in your error or shutdown handler.
<?php
try {
$var = new DateTime('some invalid date format');
}
catch (Exception $ex) {}
$warning = error_get_last(); // will contain warning info
?>
Be careful working with MySQL dates representing point of transition to Daylight Saving Time.
The constructor of DateTime will convert timezone abbreviation to DST but not the time.
<?php
$timeZone = new DateTimeZone('Europe/Sofia');
$transitionToDst = '2014-03-30 03:00:00';
$date = new DateTime($transitionToDst, $timeZone);
// Outputs: Sun Mar 30, 2014 3:00:00 EEST
// Correct: Sun Mar 30, 2014 4:00:00 EEST
echo $date->format('D M j, Y G:i:s T') . '<br>';
// Explicitly setting timezone or adding one second fixes this
$cloneForAdding = clone $date;
$date->setTimezone($timeZone);
// Outputs: Sun Mar 30, 2014 4:00:00 EEST
echo $date->format('D M j, Y G:i:s T') . '<br>';
$cloneForAdding->add(new DateInterval('PT1S'));
// Outputs: Sun Mar 30, 2014 4:00:01 EEST
echo $cloneForAdding->format('D M j, Y G:i:s T');
?>
"The $timezone parameter and the current timezone are ignored when the $time parameter […] is a UNIX timestamp."
Watch out – this means that these two are NOT equivalent, they result in different timezones (unless your current timezone is GMT):
<?php
$d = new DateTime(); $d->setTimestamp($t);
echo $o->format('O');
// +0200
$d = new DateTime('@' . $t);
echo $o->format('O');
// +0000
?>
Although this function throws an exception on invalid $time values (empty strings, for example), the exception can't be caught because it's a fatal exception. Use functions such as checkdate() and strtotime() to validate the string first. Example #1 should be changed to remove the try/catch block, since it's misleading.
About constructing a DateTime, instead of just using the year it seems working when date matches the pattern "YYYY-MM"
- Returns the year correctly: "YYYY-MM"
$ cat date.php
<?php
$date = new DateTime('2015-12');
echo($date->format('Y'));
?>
$ php date.php
2015
- Ignores the given input and returns the year from NOW: "YYYY"
$ cat date.php
<?php
$date = new DateTime('2015');
echo($date->format('Y'));
?>
$ php date.php
2019
RESULTS/SCOPE:
- Linux (May 24, 2019)
- PHP 7.2.17 (cli)
Using this in a try catch to verify a string is in a valid date format is unreliable. Single letter strings used for the first argument (time string) of the constructor allows a new instance of the class to be created, without any exception or error.
So the below code would not fail or throw an exception. So $time would not be an empty string.
$value = 'y';
try {
$time = new \DateTimeZone($value);
} catch (\Exception $e) {
$time = '';
}
I'm surprised this hasn't been mentioned, but when constructing a DateTime with just the year as a string, DateTime will pre-initialize itself with NOW and then replace the year, so if today is 7/12/2016:
<?php
print((new DateTime('2015'))->modify('+1 day')->format('Y-m-d'));
?>
results in 2016-07-13
This seems to work as expected, at least now:
<?php
$timezone1 = new \DateTimeZone('Europe/Sofia');
$timezone2 = new \DateTimeZone('UTC');
$sometime1 = '2014-03-30 02:59:59';
$sometime2 = '2014-03-30 03:00:00';
$date1 = new \DateTime($sometime1, $timezone1);
$date2 = new \DateTime($sometime2, $timezone1);
echo $date1->format('D M j, Y G:i:s T') . '<br>';
echo $date2->format('D M j, Y G:i:s T') . '<br>';
$date1->setTimezone($timezone1);
$date2->setTimezone($timezone1);
echo $date1->format('D M j, Y G:i:s T') . '<br>';
echo $date2->format('D M j, Y G:i:s T') . '<br>';
$date1->setTimezone($timezone2);
$date2->setTimezone($timezone2);
echo $date1->format('D M j, Y G:i:s T') . '<br>';
echo $date2->format('D M j, Y G:i:s T') . '<br>';
This outputs:
Sun Mar 30, 2014 2:59:59 EET
Sun Mar 30, 2014 4:00:00 EEST
Sun Mar 30, 2014 2:59:59 EET
Sun Mar 30, 2014 4:00:00 EEST
Sun Mar 30, 2014 0:59:59 UTC
Sun Mar 30, 2014 1:00:00 UTC
<?php
$timestampNow = time();
$timestamp = $timestampNow + 13;
$datetime = new \DateTime("@{$timestamp}", new \DateTimeZone('Europe/Berlin'));
echo $datetime->getTimezone()->getName(); // +00:00 !!!!
?>
Does NOT work. You get UTC always.
See comment http://php.net/manual/en/datetime.construct.php#106979
use relative format instead:
<?php
$sec = 13;
$datetime = new \DateTime("now + {$sec} sec", new \DateTimeZone('Europe/Berlin'));
echo $datetime->getTimezone()->getName(); // Europe/Berlin
?>
see http://php.net/manual/en/datetime.formats.relative.php
Also forgot to mention, that MySQL "zeroed" dates do not throw an error but produce a non-sensical date:
<?php
$d = new DateTime("0000-00-00");
$d->format("Y-m-d"); // "-0001-11-30"
?>
Another good reason to write your own class that extends from DateTime.
When passing a non US or SQL date string the date will be formatted incorrectly.
// UK date d/m/Y.
$date_time = "08/03/2016 00:00:00";
$dt = new DateTime($date_time, new DateTimeZone("Europe/London"));
// Gives 2016-08-03
echo $dt->format("Y-m-d");
Impossible times due to daylight savings are handled by this function in a way similar to impossible dates, with the difference that this is not an error (i.e. a consequent call to DateTime::getLastError() yields nothing).
For example:
In the timezone "Europe/Berlin" on Sunday, March 30 2014 there was no 02:30 am, because that our is being skipped due to daylight savings on that day.
<?php
$tz = new DateTimeZone("Europe/Berlin");
$impossible_time = "2014-03-30T02:30:00";
$date = new DateTime($impossible_time, $tz);
var_dump($date->getLastErrors());
echo "The impossible time '$impossible_time' is interpreted as: " . $date->format(DateTime::ISO8601) . "\n";
/*
Yields:
array(4) {
'warning_count' =>
int(0)
'warnings' =>
array(0) {
}
'error_count' =>
int(0)
'errors' =>
array(0) {
}
}
The impossible time '2014-03-30T02:30:00' is interpreted as: 2014-03-30T03:30:00+0200
*/
?>
That is similar to how, for example, Febuary 29, 2014 would be handled, which would be interpreted as March 1, 2014. The difference is, that with the date that would be an error, with the time it is not.
Ambigous times due to daylight savings are handled as the second possibility. For example the time 2:30 am occurred twice on October 26, 2014 in the timezone "Europe/Berlin".
<?php
$tz = new DateTimeZone("Europe/Berlin");
$ambiguous_time = "2014-10-26T02:30:00";
$date = new DateTime($ambiguous_time, $tz);
echo "The ambiguous time '$ambiguous_time' is interpreted as: " . $date->format(DateTime::ISO8601) . "\n";
/*
Yields:
The ambiguous time '2014-10-26T02:30:00' is interpreted as: 2014-10-26T02:30:00+0100
*/
?>
Note that "2014-10-26T02:30:00+0200", one hour earlier, would be a correct answer as well.
Since PHP 7.1 behavior of this constructor without arguments have changed.
From now on microseconds are filled with actual value. In versions <=7.0 microseconds ware set to '000000'
