number of Mondays
Carlos Hernandez wrote:
dear All, i'm trying to calculate the number of Mondays, Tuesdays, etc that each month within a date range has. I have time series data that spans 60 months and i want to calculate the number of Mondays, Tuesdays, Wed, etc of each month. (I want to control for weekly seasonality but my data is monthly). Is there an easy way to to this in R? or is there a package i could use? i did some quick search in the help files and R sites but could not find any answers. i appreciate any hint you could give,
This is where POSIXlt objects are useful:
unlist(unclass(as.POSIXlt(ISOdate(1959,3,11))))
sec min hour mday mon year wday yday isdst
0 0 12 11 2 59 3 69 0
Which means that I was born on a Wednesday (wday==3) in March (mon==2)
(some of the fields count from 0 and others, like mday, from 1;
presumably some UNIX vendor back in the Stone Age got their
implementation turned into a standard...).
This allows you to do stuff like:
dd <- seq(Sys.Date(),as.Date("2009-3-11"),1)
dd <- as.POSIXlt(dd)
with(dd, table(mon,wday))
wday mon 0 1 2 3 4 5 6 0 2 2 2 2 3 3 3 1 4 4 4 4 4 4 4 2 2 2 2 2 1 1 1 which I think is pretty much what you were looking for.
thanks. Carlos
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907