Hi, I've been playing with:> joinDate <- format(strptime(as.vector(forum[,2]), "%d-%b-%y"),+ "%d-%b-%Y")> today <- format(strptime(as.vector("14-Jun-04"), "%d-%b-%Y"),+ "%d-%b-%Y")> joinDate[1] "04-Feb-2004" "13-Feb-2004" "26-Feb-2004" "27-Feb-2004" "27-Feb-2004" [6] "27-Feb-2004" "29-Feb-2004" "01-Mar-2004" "02-Mar-2004" "07-Mar-2004" [11] "08-Mar-2004" "17-Mar-2004" "20-Mar-2004" "22-Mar-2004" "22-Mar-2004" [16] "23-Mar-2004" "23-Mar-2004" "24-Mar-2004" "01-Apr-2004" "01-Apr-2004" [21] "01-Apr-2004" "01-Apr-2004" "02-Apr-2004" "06-Apr-2004" "09-Apr-2004" [26] "11-Apr-2004" "14-Apr-2004" "03-May-2004" "04-May-2004" "30-May-2004" [31] "01-Jun-2004" "10-Jun-2004" "14-Jun-2004" "17-Jun-2004" "17-Jun-2004"> today[1] "14-Jun-0004"> joinDate - todayError in joinDate - today : non-numeric argument to binary operator But it didn't quite work. What I'd like joinDate - today to return is the number of days to today, since joinDate. I'm sure it has been asked before however a search on r-help didn't found me any relevant information *_*. Cheers, Kevin -------------------------------------------- Ko-Kang Kevin Wang, MSc(Hon) SLC Stats Workshops Co-ordinator The University of Auckland New Zealand
You have formatted the dates, so you are trying to subtract character strings. Convert to Date instead (although you can subtract POSIXlt dates). On Thu, 17 Jun 2004, Ko-Kang Kevin Wang wrote:> Hi, > > I've been playing with: > > joinDate <- format(strptime(as.vector(forum[,2]), "%d-%b-%y"), > + "%d-%b-%Y") > > today <- format(strptime(as.vector("14-Jun-04"), "%d-%b-%Y"), > + "%d-%b-%Y") > > joinDate > [1] "04-Feb-2004" "13-Feb-2004" "26-Feb-2004" "27-Feb-2004" > "27-Feb-2004" > [6] "27-Feb-2004" "29-Feb-2004" "01-Mar-2004" "02-Mar-2004" > "07-Mar-2004" > [11] "08-Mar-2004" "17-Mar-2004" "20-Mar-2004" "22-Mar-2004" > "22-Mar-2004" > [16] "23-Mar-2004" "23-Mar-2004" "24-Mar-2004" "01-Apr-2004" > "01-Apr-2004" > [21] "01-Apr-2004" "01-Apr-2004" "02-Apr-2004" "06-Apr-2004" > "09-Apr-2004" > [26] "11-Apr-2004" "14-Apr-2004" "03-May-2004" "04-May-2004" > "30-May-2004" > [31] "01-Jun-2004" "10-Jun-2004" "14-Jun-2004" "17-Jun-2004" > "17-Jun-2004" > > today > [1] "14-Jun-0004" > > joinDate - today > Error in joinDate - today : non-numeric argument to binary operator > > But it didn't quite work. What I'd like joinDate - today to return is > the number of days to today, since joinDate. I'm sure it has been asked > before however a search on r-help didn't found me any relevant > information *_*. > > Cheers, > > Kevin > > -------------------------------------------- > Ko-Kang Kevin Wang, MSc(Hon) > SLC Stats Workshops Co-ordinator > The University of Auckland > New Zealand > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > >-- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
>>>>> "KKWa" == Ko-Kang Kevin Wang <k.wang at auckland.ac.nz> >>>>> on Thu, 17 Jun 2004 19:57:39 +1200 writes:KKWa> Hi, KKWa> I've been playing with: >> joinDate <- format(strptime(as.vector(forum[,2]), "%d-%b-%y"), KKWa> + "%d-%b-%Y") >> today <- format(strptime(as.vector("14-Jun-04"), "%d-%b-%Y"), KKWa> + "%d-%b-%Y") >> joinDate KKWa> [1] "04-Feb-2004" "13-Feb-2004" "26-Feb-2004" "27-Feb-2004" KKWa> "27-Feb-2004" KKWa> [6] "27-Feb-2004" "29-Feb-2004" "01-Mar-2004" "02-Mar-2004" KKWa> "07-Mar-2004" KKWa> ................................ >> today KKWa> [1] "14-Jun-0004" >> joinDate - today KKWa> Error in joinDate - today : non-numeric argument to binary operator KKWa> But it didn't quite work. What I'd like joinDate - KKWa> today to return is the number of days to today, since KKWa> joinDate. I'm sure it has been asked before however a KKWa> search on r-help didn't found me any relevant KKWa> information *_*. Kevin, [[did you have tough day? usually your Q/A are much better ;-()]] both joinDate and today are results of format() and hence character vectors (with no time information left). You didn't really expect "-" to work with characters? OTOH, "-" properly does work with POSIX*t objects, see, e.g., ?difftime Regards, Martin