easter_date

(PHP 4, PHP 5)

easter_dateGet Unix timestamp for midnight on Easter of a given year

Descrierea

int easter_date ([ int $year = date("Y") ] )

Returns the Unix timestamp corresponding to midnight on Easter of the given year.

Avertizare

This function will generate a warning if the year is outside of the range for Unix timestamps (i.e. before 1970 or after 2037).

The date of Easter Day was defined by the Council of Nicaea in AD325 as the Sunday after the first full moon which falls on or after the Spring Equinox. The Equinox is assumed to always fall on 21st March, so the calculation reduces to determining the date of the full moon and the date of the following Sunday. The algorithm used here was introduced around the year 532 by Dionysius Exiguus. Under the Julian Calendar (for years before 1753) a simple 19-year cycle is used to track the phases of the Moon. Under the Gregorian Calendar (for years after 1753 - devised by Clavius and Lilius, and introduced by Pope Gregory XIII in October 1582, and into Britain and its then colonies in September 1752) two correction factors are added to make the cycle more accurate.

Parametri

year

The year as a number between 1970 an 2037. If omitted, defaults to the current year according to the local time.

Valorile întoarse

The easter date as a unix timestamp.

Exemple

Example #1 easter_date() example

<?php

echo date("M-d-Y"easter_date(1999));        // Apr-04-1999
echo date("M-d-Y"easter_date(2000));        // Apr-23-2000
echo date("M-d-Y"easter_date(2001));        // Apr-15-2001

?>

Note

Notă:

easter_date() relies on your system's C library time functions, rather than using PHP's internal date and time functions. As a consequence, easter_date() uses the TZ environment variable to determine the time zone it should operate in, rather than using PHP's default time zone, which may result in unexpected behaviour when using this function in conjunction with other date functions in PHP.

As a workaround, you can use the easter_days() with DateTime and DateInterval to calculate the start of Easter in your PHP time zone as follows:

<?php
function get_easter_datetime($year) {
    
$base = new DateTime("$year-03-21");
    
$days easter_days($year);

    return 
$base->add(new DateInterval("P{$days}D"));
}

foreach (
range(20122015) as $year) {
    
printf("Easter in %d is on %s\n",
           
$year,
           
get_easter_datetime($year)->format('F j'));
}
?>

Exemplul de mai sus va afișa:

Easter in 2012 is on April 8
Easter in 2013 is on March 31
Easter in 2014 is on April 20
Easter in 2015 is on April 5

Vedeți de asemenea

  • easter_days() - Get number of days after March 21 on which Easter falls for a given year for calculating Easter before 1970 or after 2037

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User Contributed Notes 9 notes

up
3
py dot lebecq at gmail dot com
4 years ago
I recently had to write a function that allows me to know if today is a holiday.

And in France, we have some holidays which depends on the easter date. Maybe this will be helpful to someone.

Just modify in the $holidays array the actual holidays dates of your country.

<?php
/**
* This function returns an array of timestamp corresponding to french holidays
*/
protected static function getHolidays($year = null)
{
  if (
$year === null)
  {
   
$year = intval(date('Y'));
  }
   
 
$easterDate  = easter_date($year);
 
$easterDay   = date('j', $easterDate);
 
$easterMonth = date('n', $easterDate);
 
$easterYear   = date('Y', $easterDate);

 
$holidays = array(
   
// These days have a fixed date
   
mktime(0, 0, 0, 11$year),  // 1er janvier
   
mktime(0, 0, 0, 51$year),  // Fête du travail
   
mktime(0, 0, 0, 58$year),  // Victoire des alliés
   
mktime(0, 0, 0, 714, $year),  // Fête nationale
   
mktime(0, 0, 0, 815, $year),  // Assomption
   
mktime(0, 0, 0, 11, 1$year),  // Toussaint
   
mktime(0, 0, 0, 11, 11, $year),  // Armistice
   
mktime(0, 0, 0, 12, 25, $year),  // Noel

    // These days have a date depending on easter
   
mktime(0, 0, 0, $easterMonth, $easterDay + 2$easterYear),
   
mktime(0, 0, 0, $easterMonth, $easterDay + 40, $easterYear),
   
mktime(0, 0, 0, $easterMonth, $easterDay + 50, $easterYear),
  );

 
sort($holidays);
 
  return
$holidays;
}
?>
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2
maxie
6 years ago
To compute the correct Easter date for Eastern Orthodox Churches I made a function based on the Meeus Julian algorithm:

<?php
function orthodox_eastern($year) {
   
$a = $year % 4;
   
$b = $year % 7;
   
$c = $year % 19;
   
$d = (19 * $c + 15) % 30;
   
$e = (2 * $a + 4 * $b - $d + 34) % 7;
   
$month = floor(($d + $e + 114) / 31);
   
$day = (($d + $e + 114) % 31) + 1;
   
   
$de = mktime(0, 0, 0, $month, $day + 13, $year);
   
    return
$de;
}
?>
up
1
Guillaume Dufrene
1 year ago
I found a problem with holidays timestamp computation and daylight saving time.
An article about it at http://goo.gl/76t31 (in french only, sorry).

In summary, this year (2013) easter begins before adding an hour for daylight saving time (occured sunday at 3:00). It means that if you do $easter + X, where x is a number of seconds equivalent to one day, 39 days or 50 days, the result is not equals to a midnight timestamp...

Here a function to check if a midnight timestamp is equals to an holiday :

function isHoliday( $ts ) {
// Licence : Creative Commons (BY)
// By Webpulser - http://goo.gl/76t31
  $fixed_holidays = array( ’01-01′, ’01-05′, ’08-05′, ’14-07′, ’15-08′, ’11-11′, ’25-12′ );
  $format = ‘d-m’;

$dm = date($format, $ts);
  if ( in_array($dm, $fixed_holidays) ) return true;

$easter = easter_date( date(‘Y’, $ts) );
  if ( date($format, $easter +   86400) == $dm ) return true;
  if ( date($format, $easter + 3369600) == $dm ) return true;
  if ( date($format, $easter + 4320000) == $dm ) return true;

return false;
}

feel free to use / modify.
up
0
adwil at live dot com
8 months ago
Hey, recently I needed a function to get realization dates in online shop, so here it is (ready to go for polish users, please adjust your dates for any other country):

<?php
function getWorkday($date1,$workDays) {
       
$workDays = (int)$workDays;
        if (
$workDays <= 0)
            return
null;

       
$date1=strtotime('-1 day',strtotime($date1));

       
$lastYear = null;
       
$hol=array('01-01','01-06','05-01','05-03','08-15','11-01','11-11','12-25','12-26');  //array of month-date of static holidays (these are from Poland)
       
$i = 0;
        while (
$i<=$workDays) {
           
$year = date('Y', $date1);
            if (
$year !== $lastYear){
               
$lastYear = $year;
               
$easter = date('m-d', easter_date($year));
               
$date = strtotime($year . '-' . $easter); // easter
               
$easterSec = date('m-d', strtotime('+1 day', $date)); // easter monday
               
$greens = date('m-d', strtotime('+49 days', $date)); // zielone swiatki
               
$cc = date('m-d', strtotime('+60 days', $date)); // boze cialo
               
$hol[] = $easter;
               
$hol[] = $easterSec;
               
$hol[] = $greens;
               
$hol[] = $cc;
            }
           
$weekDay=date('w',$date1);
            if (!(
$weekDay==0 || $weekDay==6 || in_array(date('m-d',$date1),$hol)))
               
$i++;

           
$date1=strtotime('+1 day',$date1);
        }
        return
date('Y-m-d',$date1);
    }
?>
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0
peter dot burden at gmail dot com
4 years ago
In 5.3.1 easter_date() returns GMT of start of Easter Day in UK allowing
for UK Summer Time. If you are in another time zone you need to
calculate offsets.
<?php
        $e1
= easter_date(2008);
       
$e2 = easter_date(2009);
        echo
"Timestamps " . $e1 . " " . $e2 . "\n";

       
//      Timestamps 1206230400 1239490800

       
echo "Days between Easter 2008 Easter 2009 = " . ($e2-$e1)/86400 . "\n";

       
//      Days between Easter 2008 Easter 2009 = 384.958333333 - i.e. 384 days 23 hours

       
date_default_timezone_set("Europe/London");
        echo
date( " l, jS F Y H:i TO",$e1) . "\n";
        echo
date( " l, jS F Y H:i TO",$e2) . "\n";

       
//      Sunday, 23rd March 2008 00:00 GMT+0000
        //      Sunday, 12th April 2009 00:00 BST+0100

       
date_default_timezone_set("America/New_York");
        echo
date( " l, jS F Y H:i TO",$e1) . "\n";
        echo
date( " l, jS F Y H:i TO",$e2) . "\n";

       
//      Saturday, 22nd March 2008 20:00 EDT-0400
        //      Saturday, 11th April 2009 19:00 EDT-0400
        //      Daylight saving time in effect - New York 4 hours behind GMT
?>
up
0
nigelf at esp dot co dot uk
6 years ago
v5.2.1 - There is a known bug with easter_date() that can return incorrect dates for some years:

<?php
// 2008 OK
echo date("D d M Y", easter_date(2008));  // Sun 23 Mar 2008

// 2009 returns Saturday
echo date("D d M Y", easter_date(2009));  // Sat 11 Apr 2009
?>


However easter_days() works correctly:

<?php
echo date("D d M Y", strtotime("2009-03-21 +".easter_days(2009)." days"));  // Sun 12 Apr 2009
?>

It is apparently related to timezone settings.
up
0
Anonymous
8 years ago
I made the function like this ... works fine !

<?php
function ostern
{
   
$maerz21=date('z',mktime(0,0,0,3,21,$jb));

   
$d=((15 + $jb/100 - $jb/400 - (8 * $jb/100 + 13) / 25)%30 + 19 * ($jb%19))%30;

    if (
$d==29)
    {
       
$D=28;
    }
    elseif(
$d==28 && ($jb%17)>=11)
    {
       
$D=27;
    }
    else
$D=$d;   

   
$e=(2 * ($jb%4) + 4 *($jb%7) + 6 * $D + (6 + $jb/100 - $jb/400 - 2)%7)%7;

   
$ostersonntag=$e+$D+1+$maerz21;
    return
$ostersonntag;
}
?>
up
0
phpuser
10 years ago
The algorithm from Bigtree is correct if you add some (int) cast
<?php
  
function easter_date ($Year) {
  
      
/*
       G is the Golden Number-1
       H is 23-Epact (modulo 30)
       I is the number of days from 21 March to the Paschal full moon
       J is the weekday for the Paschal full moon (0=Sunday,
         1=Monday, etc.)
       L is the number of days from 21 March to the Sunday on or before
         the Paschal full moon (a number between -6 and 28)
       */
      

        
$G = $Year % 19;
        
$C = (int)($Year / 100);
        
$H = (int)($C - (int)($C / 4) - (int)((8*$C+13) / 25) + 19*$G + 15) % 30;
        
$I = (int)$H - (int)($H / 28)*(1 - (int)($H / 28)*(int)(29 / ($H + 1))*((int)(21 - $G) / 11));
        
$J = ($Year + (int)($Year/4) + $I + 2 - $C + (int)($C/4)) % 7;
        
$L = $I - $J;
        
$m = 3 + (int)(($L + 40) / 44);
        
$d = $L + 28 - 31 * ((int)($m / 4));
        
$y = $Year;
        
$E = mktime(0,0,0, $m, $d, $y);

         return
$E;

   }
?>
up
-1
luca at musician dot org
2 years ago
Due to range limitations of core functions such as easter_date(), mktime(), strtotime(), I wrote this function to get the Easter Day in string format yyyy-mm-dd.

function myEaster($year)
{
    /*Warning: easter_date(): This function is only valid for years between 1970 and 2037
     * The easter_days() function can be used instead of easter_date() to calculate Easter for years which fall outside the range.
      */
     //The next line would do the work if there were no limitations:
    //return date("Y-m-d",easter_date($year));

    /*Outside range (1970,2037) they advise to use easter_days().
     * Unfortunately, when you have to create a date object as 21-03-yyyy to which add easter_days(), then obtain Easter,
     * functions like strtotime(), DateTime::createFromFormat() will fail. (return value is 01-01-1970)
     */
    $march21=date("$year-03-21");
    $days=easter_days($year);
    if($year<=2037)
    //The next line would do the work if strtotime() wasn't affected by same limitations. But, the if..else is required to handle all years.
        $date = date("Y-m-d",strtotime(date("Y-m-d", strtotime($march21)) . " +$days day"));
    else
    {
        if($days<=10){
            $day=str_pad(21+$days, 2, '0', STR_PAD_LEFT);
            $date=date("$year-03-$day");
        }
        else
        {
            $day=str_pad($days-10, 2, '0', STR_PAD_LEFT);
            $date=date("$year-04-$day");
        }
    }

    return $date;
}
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