The DateTime class

(PHP 5 >= 5.2.0, PHP 7)

Introduction

Representation of date and time.

Class synopsis

DateTime implements DateTimeInterface {

/* Constants */

const string ATOM = "Y-m-d\TH:i:sP" ;

const string COOKIE = "l, d-M-Y H:i:s T" ;

const string ISO8601 = "Y-m-d\TH:i:sO" ;

const string RFC822 = "D, d M y H:i:s O" ;

const string RFC850 = "l, d-M-y H:i:s T" ;

const string RFC1036 = "D, d M y H:i:s O" ;

const string RFC1123 = "D, d M Y H:i:s O" ;

const string RFC2822 = "D, d M Y H:i:s O" ;

const string RFC3339 = "Y-m-d\TH:i:sP" ;

const string RSS = "D, d M Y H:i:s O" ;

const string W3C = "Y-m-d\TH:i:sP" ;

/* Methods */

public __construct ([ string $time = "now" [, DateTimeZone $timezone = NULL ]] )

public DateTime add ( DateInterval $interval )

public static DateTime createFromFormat ( string $format , string $time [, DateTimeZone $timezone = date_default_timezone_get() ] )

public static array getLastErrors ( void )

public DateTime modify ( string $modify )

public static DateTime __set_state ( array $array )

public DateTime setDate ( int $year , int $month , int $day )

public DateTime setISODate ( int $year , int $week [, int $day = 1 ] )

public DateTime setTime ( int $hour , int $minute [, int $second = 0 ] )

public DateTime setTimestamp ( int $unixtimestamp )

public DateTime setTimezone ( DateTimeZone $timezone )

public DateTime sub ( DateInterval $interval )

public DateInterval diff ( DateTimeInterface $datetime2 [, bool $absolute = false ] )

public string format ( string $format )

public int getOffset ( void )

public int getTimestamp ( void )

public DateTimeZone getTimezone ( void )

public __wakeup ( void )

}

Predefined Constants

DateTime::ATOM
DATE_ATOM: Atom (example: 2005-08-15T15:52:01+00:00)
DateTime::COOKIE
DATE_COOKIE: HTTP Cookies (example: Monday, 15-Aug-2005 15:52:01 UTC)
DateTime::ISO8601
DATE_ISO8601: ISO-8601 (example: 2005-08-15T15:52:01+0000)
Note: This format is not compatible with ISO-8601, but is left this way for backward compatibility reasons. Use DateTime::ATOM or DATE_ATOM for compatibility with ISO-8601 instead.
DateTime::RFC822
DATE_RFC822: RFC 822 (example: Mon, 15 Aug 05 15:52:01 +0000)
DateTime::RFC850
DATE_RFC850: RFC 850 (example: Monday, 15-Aug-05 15:52:01 UTC)
DateTime::RFC1036
DATE_RFC1036: RFC 1036 (example: Mon, 15 Aug 05 15:52:01 +0000)
DateTime::RFC1123
DATE_RFC1123: RFC 1123 (example: Mon, 15 Aug 2005 15:52:01 +0000)
DateTime::RFC2822
DATE_RFC2822: RFC 2822 (example: Mon, 15 Aug 2005 15:52:01 +0000)
DateTime::RFC3339
DATE_RFC3339: Same as DATE_ATOM (since PHP 5.1.3)
DateTime::RSS
DATE_RSS: RSS (example: Mon, 15 Aug 2005 15:52:01 +0000)
DateTime::W3C
DATE_W3C: World Wide Web Consortium (example: 2005-08-15T15:52:01+00:00)

Changelog

Version	Description
5.5.0	The class now implements DateTimeInterface.
5.4.24	The COOKIE constant was changed to reflect RFC 1036 using a four digit year rather than a two digit year (RFC 850) as prior versions.
5.2.2	DateTime object comparison with the comparison operators changed to work as expected. Previously, all DateTime objects were considered equal (using ==).

DateTime::add — Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
DateTime::__construct — Returns new DateTime object
DateTime::createFromFormat — Returns new DateTime object formatted according to the specified format
DateTime::getLastErrors — Returns the warnings and errors
DateTime::modify — Alters the timestamp
DateTime::__set_state — The __set_state handler
DateTime::setDate — Sets the date
DateTime::setISODate — Sets the ISO date
DateTime::setTime — Sets the time
DateTime::setTimestamp — Sets the date and time based on an Unix timestamp
DateTime::setTimezone — Sets the time zone for the DateTime object
DateTime::sub — Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object

User Contributed Notes

php at keith tyler dot com

3 years ago


DateTime does not support split seconds (microseconds or milliseconds etc.)
I don't know why this isn't documented.
The class constructor will accept them without complaint, but they are discarded.
There does not appear to be a way to take a string like "2012-07-08 11:14:15.638276" and store it in an objective form in a complete way.

So you cannot do date math on two strings such as:

<?php
$d1=new DateTime("2012-07-08 11:14:15.638276");
$d2=new DateTime("2012-07-08 11:14:15.889342");
$diff=$d2->diff($d1);
print_r( $diff ) ;

/* returns:

DateInterval Object
(
    [y] => 0
    [m] => 0
    [d] => 0
    [h] => 0
    [i] => 0
    [s] => 0
    [invert] => 0
    [days] => 0
)

*/
?>

You get back 0 when you actually want to get 0.251066 seconds.

michael at smith-li dot com

3 months ago


DateTime supports microseconds since 5.2.2. This is mentioned in the documentation for the date function, but bears repeating here. You can create a DateTime with fractional seconds and retrieve that value using the 'u' format string.

<?php
// Instantiate a DateTime with microseconds.
$d = new DateTime('2011-01-01T15:03:01.012345Z');

// Output the microseconds.
echo $d->format('u'); // 012345

// Output the date with microseconds.
echo $d->format('Y-m-d\TH:i:s.u'); // 2011-01-01T15:03:01.012345

julie at earthshod dot co dot uk

2 years ago


It isn't obvious from the above, but you can insert a letter of the alphabet directly into the date string by escaping it with a backslash in the format string.  Note that if you are using "double" speech marks around the format string, you will have to further escape each backslash with another backslash!  If you are using 'single' speech marks around the format string, then you only need one backslash.

For instance, to create a string like "Y2014M01D29T1633", you *could* use string concatenation like so:

<?php
    $dtstring = "Y" . date("Y", $when) . "M" . date("m", $when) . "D" . date("d", $when) . "T" . date("Hi", $when);
?>

but you could also escape the letters with backslashes like so:

<?php
    $dtstring1 = date('\YY\Mm\Dd\THi', $when);
    $dtstring2 = date("\\YY\\Mm\\Dd\\THi", $when);
?>

This method involves fewer function calls, so probably is slightly quicker; and also is immune to race conditions if you are not specifying the second argument.  [It's possible that you could evaluate date("d") just *before* midnight and date("H") just *after* midnight.  This will not give you the result you were expecting.]

gmblar+php at gmail dot com

6 years ago


Small but powerful extension to DateTime

<?php

class Blar_DateTime extends DateTime {

    /**
     * Return Date in ISO8601 format
     *
     * @return String
     */
    public function __toString() {
        return $this->format('Y-m-d H:i');
    }

    /**
     * Return difference between $this and $now
     *
     * @param Datetime|String $now
     * @return DateInterval
     */
    public function diff($now = 'NOW') {
        if(!($now instanceOf DateTime)) {
            $now = new DateTime($now);
        }
        return parent::diff($now);
    }

    /**
     * Return Age in Years
     *
     * @param Datetime|String $now
     * @return Integer
     */
    public function getAge($now = 'NOW') {
        return $this->diff($now)->format('%y');
    }

}

?>

Usage:

<?php

$birthday = new Blar_DateTime('1879-03-14');

// Example 1
echo $birthday;
// Result: 1879-03-14 00:00

// Example 2
echo '<p>Albert Einstein would now be ', $birthday->getAge(), ' years old.</p>';
// Result: <p>Albert Einstein would now be 130 years old.</p>

// Example 3
echo '<p>Albert Einstein would now be ', $birthday->diff()->format('%y Years, %m Months, %d Days'), ' old.</p>';
// Result: <p>Albert Einstein would now be 130 Years, 10 Months, 10 Days old.</p>

// Example 4
echo '<p>Albert Einstein was on 2010-10-10 ', $birthday->getAge('2010-10-10'), ' years old.</p>';
// Result: <p>Albert Einstein was on 2010-10-10 131 years old.</p>

?>

tim at timfennis dot com

3 years ago


There is a subtle difference between the following two statments which causes JavaScript's Date object on iPhones to fail.

<?php
$objDateTime = new DateTime('NOW');
echo $objDateTime->format('c'); // ISO8601 formated datetime
echo $objDateTime->format(DateTime::ISO8601); // Another way to get an ISO8601 formatted string

/**
On my local machine this results in: 

2013-03-01T16:15:09+01:00
2013-03-01T16:15:09+0100

Both of these strings are valid ISO8601 datetime strings, but the latter is not accepted by the constructor of JavaScript's date object on iPhone. (Possibly other browsers as well)
*/

?>

Our solution was to create the following constant on our DateHelper object.

<?php
class DateHelper
{
    /**
     * An ISO8601 format string for PHP's date functions that's compatible with JavaScript's Date's constructor method
     * Example: 2013-04-12T16:40:00-04:00
     * 
     * PHP's ISO8601 constant doesn't add the colon to the timezone offset which is required for iPhone
    **/
    const ISO8601 = 'Y-m-d\TH:i:sP';
}
?>

bf at tbwb dot nl

5 years ago


If you have timezone information in the time string you construct the DateTime object with, you cannot add an extra timezone in the constructor. It will ignore the timezone information in the time string:

$date = new DateTime("2010-07-05T06:00:00Z", new DateTimeZone("Europe/Amsterdam"));

will create a DateTime object set to "2010-07-05 06:00:00+0200" (+2 being the TZ offset for Europe/Amsterdam)

To get this done, you will need to set the timezone separately:

$date = new DateTime("2010-07-05T06:00:00Z");
$date->setTimeZone(new DateTimeZone("Europe/Amsterdam");

This will create a DateTime object set to "2010-07-05 08:00:00+0200"

stevenmattera at gmail dot com

2 years ago


This caused some confusion with a blog I was working on and just wanted to make other people aware of this. If you use createFromFormat to turn a date into a timestamp it will include the current time. For example:

<?php
$publishDate = DateTime::createFromFormat('m/d/Y', '1/10/2014');
echo $publishDate->getTimestamp();
?>

Would not output the expected "1389312000" instead it would output something more like "1389344025". To fix this you would want to do:

<?php
$publishDate = DateTime::createFromFormat('m/d/Y', '1/10/2014');
$publishDate->setTime(0, 0, 0);
echo $publishDate->getTimestamp();
?>

I hope this helps someone!

nodweber at gmail dot com

4 years ago


IF You want to create clone of $time, use clone..

<?php
  $now   = new DateTime;
  $clone = $now;        //this doesnot clone so:
  $clone->modify( '-1 day' );
 
  echo $now->format( 'd-m-Y' ), "\n", $clone->format( 'd-m-Y' );
  echo '----', "\n";

  // will print same.. if you want to clone make like this:
  $now   = new DateTime;
  $clone = clone $now;    
  $clone->modify( '-1 day' );
    
  echo $now->format( 'd-m-Y' ), "\n", $clone->format( 'd-m-Y' );
?>

Results:
18-07-2011
18-07-2011
----
19-07-2011
18-07-2011

giorgio dot liscio at email dot it

5 years ago


please note that using



setTimezone

setTimestamp

setDate

setTime

etc..



will modify the original object, and the return value is $this



$original = new DateTime("now");



$modified = $original->setTimezone(new DateTimezone("europe/rome"));



echo $original === $modified ? "THE OBJECT IS THE SAME" : "OBJECTS ARE DIFFERENT";



so a datetime object is mutable



(Editors note: PHP 5.5 adds DateTimeImmutable which does not modify the original object, instead creating a new instance.)

anthony at teamug dot net

7 months ago


This is a great class, but unless you need to use it's more advanced features, I would stick to passing times around your scripts as Unix Time Stamps - maybe prefixing with "uts".
Otherwise you will simply be creating more lines of code with no benefit.

ph at jokerss dot com dot br

2 months ago


Create function to convert GregorianDate to JulianDayCount

<?php

function dateJulian($date) {
        $dateTime = new DateTime($date);
        $limitDate = new DateTime('01-03-'.$dateTime->format('Y'));
        $diff = $dateTime->diff($limitDate);
        $soma = 1;
        if ($dateTime->format('L') && $diff->invert) {
                $soma = 2;
        }
        return ( (int) $dateTime->format('z')) + $soma;
}

echo PHP_EOL,dateJulian('01-03-2015'), PHP_EOL;
echo PHP_EOL,dateJulian('01-03-2016'), PHP_EOL;

/**
  * returns 
  * 60 
  * 61
  */

?>

ryan at amst dot com

8 months ago


It seems like, due to changes in the DateTimeZone class in PHP 5.5, when creating a date and specifying the timezone as a a string like 'EDT', then getting the timezone from the date object and trying to use that to set the timezone on a date object you will have problems but never know it.  Take the following code:

<?php
$date = new DateTime('2015-08-21 15:00:00 EDT') ;
$tz_string = $date->getTimezone()->getName() ;
$tz = new DateTimeZone($tz_string) ;
$date->setTimezone($tz) ;
?>

You would think this code should not change $date at all, but it does.  It seems like you can create a timezone object like 'EDT' but can't use those to set timezones properly.  The process, however does act like it's working without errors.

tom at r dot je

6 years ago


If you're stuck on a PHP 5.1 system (unfortunately one of my clients is on a rather horrible webhost who claims they cannot upgrade php) you can use this as a quick workaround:

<?php
if (!class_exists('DateTime')) {
class DateTime {
    public $date;
    
    public function __construct($date) {
        $this->date = strtotime($date);
    }
    
    public function setTimeZone($timezone) {
        return;
    }
    
    private function __getDate() {
        return date(DATE_ATOM, $this->date);    
    }
    
    public function modify($multiplier) {
        $this->date = strtotime($this->__getDate() . ' ' . $multiplier);
    }
    
    public function format($format) {
        return date($format, $this->date);
    }
}
}
?>

it is NOT perfect. Timezones and DST are not supported, but if you just need compatible basic functions this works. Feel free to complete this so it's compatible with the 5.2 datetime object.

James

2 years ago


Be aware that DateTime may ignore fractional seconds for some formats, but not when using the ISO 8601 time format, as documented by this bug:

https://bugs.php.net/bug.php?id=51950

$dateTime = DateTime::createFromFormat(
    DateTime::ISO8601,
    '2009-04-16T12:07:23.596Z'
);
// bool(false)

tdp

1 year ago


Be aware of this behaviour:

<?php
$dt1 = new \DateTime( '2014/12/31' );
$dt1->modify( '-1 month' );
$m = (int) $dt1->format( 'm' );
var_dump( $m ); // still 12 !!!

$dt2 = new \DateTime( '2014/12/30' );
$dt2->modify( '-1 month' );
$m = (int) $dt2->format( 'm' );
var_dump( $m ); // 11
?>

The method modify( '-1 month' ) appear to remove 30 days, not to subtract 1 from the month and adjust the day (if needed).

In my opinion, the former date should be adjusted to 2014/11/30, that is, the last day in the previous month.

marcio dot barbado at bdslabs dot com dot br

4 years ago


DateTime class does not use locales so here I test and compare its formating with strftime() function's one:

    <?php
      // Under UNIX, command "$ locale -a" should provide you with your server's options.

      $data_do_mysql            = "2011-09-29 23:50:26";

      echo '<strong>' . "\$data_do_mysql" . '</strong>' . ":" . $data_do_mysql . "." . '<br />' .
           '<br />';

      $dataInicial            = new DateTime(trim($data_do_mysql));

      // setlocale() used with strftime().
      $meu_locale            = setlocale(LC_ALL, "pt_BR.utf8");
      $data_inicial            = strftime("%d de %b de %Y", strtotime(trim($data_do_mysql)));

      // Outputs:
      // $data_do_mysql formatada com a classe DateTime:29-Sep-2011.
      echo '<strong>' . "\$data_do_mysql" . '</strong>' . " formatada com a classe DateTime:" . $dataInicial->format('d-M-Y') . "." . '<br />' .
           '<br />';

      // Outputs:
      // $data_do_mysql formatada com a função strftime():29 de Set de 2011.
      echo '<strong>' . "\$data_do_mysql" . '</strong>' . " formatada com a fun&ccedil;&atilde;o strftime():" . $data_inicial . "." . '<br />' .
           '<br />';

      // setlocale() fails :-(
      if (!$meu_locale)
        {
            echo "Prefiro usar DateTime.";
        }

      // Yay setlocale() :-D
      else
        {
            echo "Prefiro usar strftime().";
        }

      exit();
    ?>

ediathome

6 years ago


If you need DateTime::createFromFormat functionality in versions <5.3.0 releases you might use the following basic class which can also be combined with Tom's class. It should work for most basic formats, however you should improve this function if you need more complex formats.

<?php
class DateClass extends DateTime{

public function getTimestamp(){
    return $this->format ("U");
}

/**
*    This function calculates the number of days between the first and the second date. Arguments must be subclasses of DateTime
**/
static function differenceInDays ($firstDate, $secondDate){
    $firstDateTimeStamp = $firstDate->format("U");
    $secondDateTimeStamp = $secondDate->format("U");
    $rv = round ((($firstDateTimeStamp - $secondDateTimeStamp))/86400);
    return $rv;
}

/**
* This function returns an object of DateClass from $time in format $format. See date() for possible values for $format
**/
static function createFromFormat ($format, $time){
    assert ($format!="");
    if($time==""){ 
        return new DateClass();
    }

    $regexpArray['Y'] = "(?P<Y>19|20\d\d)";        
    $regexpArray['m'] = "(?P<m>0[1-9]|1[012])";
    $regexpArray['d'] = "(?P<d>0[1-9]|[12][0-9]|3[01])";
    $regexpArray['-'] = "[-]";
    $regexpArray['.'] = "[\. /.]";
    $regexpArray[':'] = "[:]";            
    $regexpArray['space'] = "[\s]";
    $regexpArray['H'] = "(?P<H>0[0-9]|1[0-9]|2[0-3])";
    $regexpArray['i'] = "(?P<i>[0-5][0-9])";
    $regexpArray['s'] = "(?P<s>[0-5][0-9])";

    $formatArray = str_split ($format);
    $regex = "";

    // create the regular expression
    foreach($formatArray as $character){
        if ($character==" ") $regex = $regex.$regexpArray['space'];
        elseif (array_key_exists($character, $regexpArray)) $regex = $regex.$regexpArray[$character];
    }
    $regex = "/".$regex."/";

    // get results for regualar expression
    preg_match ($regex, $time, $result);

    // create the init string for the new DateTime
    $initString = $result['Y']."-".$result['m']."-".$result['d'];

// if no value for hours, minutes and seconds was found add 00:00:00
    if (isset($result['H'])) $initString = $initString." ".$result['H'].":".$result['i'].":".$result['s'];
    else {$initString = $initString." 00:00:00";}

    $newDate = new DateClass ($initString);
    return $newDate;
    }    
}

?>

The DateTime class

Introduction

Class synopsis

Predefined Constants

Changelog

Table of Contents

User Contributed Notes