On Mon, Nov 8, 2010 at 7:06 AM, Benjamin Williams <b...@bwmcct.com> wrote: > Dear R Help, > > I am trying to get fields showing the last day of each month for a monthly > closing project. In order to find the last day of the previous month, I > subtract the number of days from the current month. For all months my code > works; however, for October, my code doesn't work...it returns > 2010-09-*29* instead > of 2010-09-*30*. > > format(strptime("2010-10-31", > "%Y-%m-%d")-(as.numeric(format(as.Date("2010-10-31"),"%d"))*24*3600),"%Y-%m-%d") >
There are many ways to do this but here is one using as.yearmon in zoo. This converts the Date variable, today, to "yearmon" class which is a year and a fraction representing a month. Then it converts it back to "Date" class using frac = 1 which means all the way to the end of the month (frac = 0, the default, means 1st of month, etc.): > library(zoo) > today <- Sys.Date() > as.Date(as.yearmon(today), frac = 1) [1] "2010-11-30" If you are trying to show monthly data another option might be just to not show the day at all: > format(as.yearmon(today)) [1] "Nov 2010" > > # or without yearmon > format(today, "%b %Y") [1] "Nov 2010" -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ R-help@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.