Auto populate week dates

Question

I'm trying to find a way to auto populate the start/end week dates for any given year. E.g. 4/12/2015 - 4/18/2015, 4/19/2015 - 4/25/2015, 4/26/2015 - 5/2/2015. I guess I could calculate those explicitly, but it's not very elegant. Thanks in advance!

Answer 1

Find first day and last days of the first week of year: read the %W, %w, %V specifications under ?strptime for more detail. Be aware that strptime conventions are very finicky (e.g. you need exactly the right number of digits), possibly operating-system-dependent, and possibly locale-dependent ...

firstday <- as.Date(strptime("2010-01-0",format="%Y-%W-%w")) ## Sunday 
lastday <- as.Date(strptime("2010-01-6",format="%Y-%W-%w"))  ## Saturday

Now set up date sequences starting from those days:

seq.Date(firstday,as.Date("2010-12-31"),by="1 week")
seq.Date(lastday,as.Date("2010-12-31"),by="1 week")

You can use e.g. paste0(year,"-01-0") if you want to do this more generally (without hard-coding the year).