library(zoo)
?yearmon
library(chron)
?month.day.year
?strptime
See R News 4/1.
On Wed, Apr 23, 2008 at 6:13 AM, Worik R <worikr at gmail.com>
wrote:> I am a bit worried I am reinventing the wheel. Isn't there a calendar
> system in R?
>
> I have written a function to add months to a date and return the number of
> days resulting. I am newish to R so I am hoping there is a package that
> can do this sort of date arithmetic for me...
>
> Worik
>
> DaysInMonths <- function(s,d){
> ## Days in d months from s
> sdate <- MSTD(s)
>
> ## Get day, month and the year
> sd <- as.double(days(sdate))
> sm <- as.double(months(sdate))
> sy <- as.double.difftime(years(sdate))
>
> sm <- sm+d
> while(sm > 12){
> sm <- sm-12
> sy <- sy+1
> }
> sdate2 <- MSTD(paste(sd,sm,sy,sep="/"))
> return(as.double(difftime(sdate2, sdate, units="days")))
> }
>
> MSTD <- function(a){
> if(class(a)[1] == "dates") return (a)
> return(dates(a, format="d/m/y"))
> }
>
> [[alternative HTML version deleted]]
>
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