Function Name:
isocalendar
Function Signature:
isocalendar()
Overview:
The instance function isocalendar() in date class returns a tuple containing
- ISO Year
- ISO Week Number
- ISO Weekday
ISO standard 8601 and ISO standard 2015:
- As per ISO standard 8601 and ISO standard 2015, Thursday is the middle day of a week.
- Hence, the ISO years always start on a Monday.
- For the above reasons, ISO year can start as yearly as 29th January or as late as 4th January of a Gregorian calendar.
- ISO years can have either 52 full weeks or 53 full weeks.
- ISO years do not have any fractional weeks during the beginning of the year or at the end of the year.
Example:
|
# import the datetime module of Python import datetime
gregorianDayOfWeek = ("Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday") isoDayOfWeek = ("ISO Monday starts at 1","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday")
yearCount = 10 yearVal = 2011
# Get the ISO year, ISO Week number, ISO day of the week # for 10 new year dates in Gregorian Calendar
yearIndex = 0
print("==========================================================================") print("Gregorian Tuple-ISO Tuple") print("==========================================================================") print("Year, Week Number, Day of the week - Year, Week Number, Day of the week") print("==========================================================================")
while(yearIndex < yearCount): gregorianNewYear = datetime.date(yearVal, 1,1) yearVal = yearVal +1 yearIndex = yearIndex + 1
gregSet = (gregorianNewYear.year,1,gregorianDayOfWeek[gregorianNewYear.weekday()]) isoSet = gregorianNewYear.isocalendar()
print("{}-({}, {}, '{}')".format(gregSet,isoSet[0],isoSet[1],isoDayOfWeek[isoSet[2]]))
print("==========================================================================")
|
Output:
|
========================================================================== Gregorian Tuple-ISO Tuple ========================================================================== Year, Week Number, Day of the week - Year, Week Number, Day of the week ========================================================================== (2011, 1, 'Saturday')-(2010, 52, 'Saturday') (2012, 1, 'Sunday')-(2011, 52, 'Sunday') (2013, 1, 'Tuesday')-(2013, 1, 'Tuesday') (2014, 1, 'Wednesday')-(2014, 1, 'Wednesday') (2015, 1, 'Thursday')-(2015, 1, 'Thursday') (2016, 1, 'Friday')-(2015, 53, 'Friday') (2017, 1, 'Sunday')-(2016, 52, 'Sunday') (2018, 1, 'Monday')-(2018, 1, 'Monday') (2019, 1, 'Tuesday')-(2019, 1, 'Tuesday') (2020, 1, 'Wednesday')-(2020, 1, 'Wednesday') ========================================================================== |
In the output the new year of 2011 as per ISO standards is printed as 52nd week of 2010.