Welcome, guest | Sign In | My Account | Store | Cart

Calculate Easter (Western) given a year (Python recipe) by Martin Diers
ActiveState Code (http://code.activestate.com/recipes/576517/)

An implementation of Butcher's Algorithm for determining the date of Easter for the Western church. Works for any date in the Gregorian calendar (1583 and onward). Returns a date object.

Python, 13 lines
Download
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
from datetime import date

def calc_easter(self, year):
    "Returns Easter as a date object."
    a = year % 19
    b = year // 100
    c = year % 100
    d = (19 * a + b - b // 4 - ((b - (b + 8) // 25 + 1) // 3) + 15) % 30
    e = (32 + 2 * (b % 4) + 2 * (c // 4) - d - (c % 4)) % 7
    f = d + e - 7 * ((a + 11 * d + 22 * e) // 451) + 114
    month = f // 31
    day = f % 31 + 1    
    return date(year, month, day)
Tags: calendar, easter