Just looking at the ambiguity in "adding a year" > dates <- as.Date(c('2007-03-01','2008-02-29')) > tmp <- as.POSIXlt(dates) > tmp$year <- tmp$year+1 > dates2 <- as.Date(tmp) > dates2 [1] "2008-03-01" "2009-03-01" > dates2 - dates Time differences in days [1] 366 366
KJ "MacQueen, Don" <macque...@llnl.gov> wrote in message news:caea785f.7cfdb%macque...@llnl.gov... > Here is an example that could probably be described as "adding a year": > > dates <- c('2008-01-01','2009-03-02') > tmp <- as.POSIXlt(dates)tmp$year <- tmp$year+1 > dates2 <- format(tmp) >> dates > [1] "2008-01-01" "2009-03-02" >> dates2 > [1] "2009-01-01" "2010-03-02" > > ## to begin to understand how it works, give the command > ## unclass(tmp) > ## (and read the help pages > ## ?as.POSIXlt > ## ?DateTimeClasses > > Another example: > > dates <- as.Date(c('2008-01-01','2009-03-02')) > tmp <- as.POSIXlt(dates) > tmp$year <- tmp$year+1 > dates2 <- as.Date(tmp) > > > > ## ?as.Date > ## ?Date > > > > > -Don > > > -- > Don MacQueen > > Lawrence Livermore National Laboratory > 7000 East Ave., L-627 > Livermore, CA 94550 > 925-423-1062 > > > > > > On 11/16/11 8:33 PM, "arunkumar1111" <akpbond...@gmail.com> wrote: > >>Hi >> >> I need to add an year to and date field in the dataframe. >> >>Please help me >> >>X Date >>1 2008-01-01 >>2 2008-02-01 >>3 2003-03-01 >> >> >>Thanks in advance >> >>-- >>View this message in context: >>http://r.789695.n4.nabble.com/Adding-a-year-to-existing-date-tp4078930p407 >>8930.html >>Sent from the R help mailing list archive at Nabble.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. > ______________________________________________ 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.