Zellers Congruence Command Line Calendar

calendar.py

import sys
from datetime import date

def zeller(day, month, year):
    if month==1 or month==2:
        month+=12
        year-=1
    h = ( ( day +( (month+1) * 26 // 10)+ year +( year // 4)+ 6 * (year // 100)+ (year // 400)) % 7 )+6
    return h%7

def year(year):
    for month in range(1,13):
        print "%s %d" % (month_name(month), year)
        day_start = zeller(1,month,year)
        print_month(month,day_start)
        
def month(month, year=2014):
    print "%s %d" % (month_name(month), year)
    day_start = zeller(1,month,year)
    print_month(month, day_start)

def print_month(month, day_start):
    days = days_in_month(month)
    print " S  M  T  W  T  F  S "
    for j in range(day_start):
        print "  ", 
    i = 1
    while i <= days:
        if i < 10:
            print "", i,
        else:
            print i,
        if (i+day_start) % 7 == 0:
            print " "
        i = i + 1
    print
    print
    
def days_in_month(month):
    days_in_months = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    return days_in_months[month]

def month_name(month):
    month_names = ['', 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'] 
    return month_names[month]

def month_number(month):
	months={'January':1, 'February':2, 'March':3, 'April':4, 'May':5, 'June':6, 'July':7, 'August':8, 'September':9, 'October':10, 'November':11, 'December':12}
	return months[month]

if len(sys.argv) == 2:
	arg_year = sys.argv[1]
	year(int(arg_year))
elif len(sys.argv) == 3:
	arg_year = int(sys.argv[1])
	arg_month = sys.argv[2]
	arg_month = int(month_number(sys.argv[2]))
	month(arg_month, arg_year)
else:
	year(2014)