easter_days
(PHP 4, PHP 5)
easter_days — Get number of days after March 21 on which Easter falls for a given year
说明
Returns the number of days after March 21 on which Easter falls for a given year. If no year is specified, the current year is assumed.
This function can be used instead of easter_date() to calculate Easter for years which fall outside the range of 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.
(The code is based on a C program by Simon Kershaw, <webmaster at ely.anglican dot org>)
参数
- year
-
The year as a number between 1970 an 2037
返回值
The number of days after March 21st that the Easter Sunday is in the given year .
更新日志
| 版本 | 说明 |
|---|---|
| Since 4.3.0 | The year parameter is optional and defaults to the current year according to the local time if omitted. |
| Since 4.3.0 | The method parameter was introduced and allows to calculate easter dates based on the Gregorian calendar during the years 1582 - 1752 when set to CAL_EASTER_ROMAN. See the calendar constants for more valid constants. |
范例
Example#1 easter_days() example
<?php
echo easter_days(1999); // 14, i.e. April 4
echo easter_days(1492); // 32, i.e. April 22
echo easter_days(1913); // 2, i.e. March 23
?>
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