UPDATE: The concepts presented here still apply, but the code is outmoded. The Joda-Time project, now in maintenance mode, advises migration to the java.time classes. See the java.time code in the Answer by Szulc. Short Answer DateTime dateTimeStart = new DateTime( “2003-W01-1”, DateTimeZone.UTC ); // Joda-Time 2.4. DateTime dateTimeStop = dateTimeStart.plusWeeks( 1 ); For details, … Read more
With the isoweek module you can do it with: from isoweek import Week d = Week(2011, 40).monday()
(An extra answer, since this method is a bit different.) This method is about using a tally table with dates and date related stuff. Then such calendar table can be used to lookup the year and week. For example Create calendar table create table REF_Calendar ( cal_date date primary key not null, cal_year smallint not … Read more
You must use Calendar.GetDayOfWeek and Calendar.GetWeekOfYear in preference to writing yourself. You can guarantee that if you write any date / time handling code yourself it will contain faults and won’t work in different locales. public class Row { public string MonthWeek { get; set; } public string Year { get; set; } public string … Read more
I think this relationship should be true and come in handy: Week of the month = Week of the year – Week of the year of first day of month + 1 We also need to make sure that “overlapping” weeks from the previous year are handeled correctly – if January 1st is in week … Read more
In order to use straight division, the day of month for the date you’re looking at needs to be adjusted according to the position (within the week) of the first day of the month. So, if your month happens to start on a Monday (the first day of the week), you can just do division … Read more
You can find the day of week and do a date add on days to get the start and end dates.. DATEADD(dd, -(DATEPART(dw, WeddingDate)-1), WeddingDate) [WeekStart] DATEADD(dd, 7-(DATEPART(dw, WeddingDate)), WeddingDate) [WeekEnd] You probably also want to look at stripping off the time from the date as well though.
Base package Using the function strftime passing the argument %V to obtain the week of the year as decimal number (01–53) as defined in ISO 8601. (More details in the documentarion: ?strftime) strftime(c(“2014-03-16”, “2014-03-17″,”2014-03-18”, “2014-01-01”), format = “%V”) Output: [1] “11” “12” “12” “01”
The definition of Week of Year is Locale dependent. How it is defined in US is discused in the other posts. For example in Germany (DIN 1355-1 / ISO 8601): the first Week* of Year is the first week with 4 or more days in the new year. *first day of week is Monday and … Read more
I had issues with the solution by @HenkHolterman even with the fix by @RobinAndersson. Reading up on the ISO 8601 standard resolves the issue nicely. Use the first Thursday as the target and not Monday. The code below will work for Week 53 of 2009 as well. public static DateTime FirstDateOfWeekISO8601(int year, int weekOfYear) { … Read more