Date/Time
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The DateTime class

(PHP 5 >= 5.2.0)

简介

Representation of date and time.

类摘要

DateTime {
/* 常量 */
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" ;
/* 方法 */
public __construct ([ string $time = "now" [, DateTimeZone $timezone = NULL ]] )
public DateTime add ( DateInterval $interval )
public static DateTime createFromFormat ( string $format , string $time [, DateTimeZone $timezone ] )
public DateInterval diff ( DateTime $datetime2 [, bool $absolute = false ] )
public string format ( string $format )
public static array getLastErrors ( void )
public int getOffset ( void )
public int getTimestamp ( void )
public DateTimeZone getTimezone ( 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 DateTime __wakeup ( void )
}

预定义常量

DateTime::ATOM
DATE_ATOM
Atom (example: 2005-08-15T15:52:01+00:00)
DateTime::COOKIE
DATE_COOKIE
HTTP Cookies (example: Monday, 15-Aug-05 15:52:01 UTC)
DateTime::ISO8601
DATE_ISO8601
ISO-8601 (example: 2005-08-15T15:52:01+0000)
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 (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 (Mon, 15 Aug 2005 15:52:01 +0000)
DateTime::W3C
DATE_W3C
World Wide Web Consortium (example: 2005-08-15T15:52:01+00:00)

更新日志

版本 说明
5.2.2 DateTime object comparison with the comparison operators changed to work as expected. Previously, all DateTime objects were considered equal (using ==).

Table of Contents

Date/Time
在线手册：中文 英文
PHP手册
PHP手册 - N: The DateTime class

用户评论:

marcio dot barbado at bdslabs dot com dot br (23-Mar-2012 02:22)

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 fun??o 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();
    ?>

nodweber at gmail dot com (19-Jul-2011 10:22)

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 (14-Aug-2010 06:24)

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

bf at tbwb dot nl (10-Aug-2010 11:19)

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"

ediathome (20-Mar-2010 09:21)

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;
    }   
}

?>

gmblar+php at gmail dot com (24-Jan-2010 04:53)

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>

?>

tom at r dot je (10-Jun-2009 04:00)

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.