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Representation of date and time.
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
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"
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;
}
}
?>
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>
?>
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.
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