Thanks everyone for clarifying my query. However I was wondering why that Date character is not preserved within a matrix? Why R forcefully changes that to numeric? I am especially concerned because as per the definition of the matrix, each element needs to be of same class. Is there any other example other than Date class which R forcefully changes to some simpler class if it placed within a matrix?
Thanks and regards, -----Original Message----- From: Gabor Grothendieck [mailto:ggrothendi...@gmail.com] Sent: 12 March 2011 02:46 To: Bogaso Christofer Cc: r-help@r-project.org Subject: Re: [R] 'Date' elements within a matrix On Fri, Mar 11, 2011 at 4:15 PM, Bogaso Christofer <bogaso.christo...@gmail.com> wrote: > Dear all, when I put date objects (class of 'Date') in a matrix it > becomes > numeric: > >> dat <- matrix(seq(as.Date("2011-01-01"), as.Date("2011-01-09"), by="1 > day"), 3) > >> dat > > [,1] [,2] [,3] > > [1,] 14975 14978 14981 > > [2,] 14976 14979 14982 > > [3,] 14977 14980 14983 > >> class(dat[1,1]) > > [1] "numeric" > > > > As it could not preserve the 'Date' characteristics after putting my > Date observations, I find it difficult to carry forward further > calculation with Dates. Can somebody help me on how to preserve the > Data properties while storing them within some matrix? If its important to you to store them in a matrix (as opposed to a data frame) then try storing them in a matrix of lists: > dd <- seq(as.Date("2011-01-01"), as.Date("2011-01-09"), by = "day") m > <- matrix(as.list(dd), 3) m[[1,1]] [1] "2011-01-01" -- 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.
