Do an 'str(dat)' and see what the structure is. When I read in your data I get:
> x V1 V2 V3 1 AAA 1000000.0 1222.312 2 AAC 100.2 0.330 > str(x) 'data.frame': 2 obs. of 3 variables: $ V1: Factor w/ 2 levels "AAA","AAC": 1 2 $ V2: num 1000000 100 $ V3: num 1222.31 0.33 > sum(x$V1) Error in Summary.factor(1:2, na.rm = FALSE) : sum not meaningful for factors > sum(x$V2) [1] 1000100 So you 'V1" might be characters which is exactly what your error message is telling you. On Fri, Mar 13, 2009 at 4:37 AM, Gundala Viswanath <gunda...@gmail.com> wrote: > Hi all, > > I have the following data > > AAA 1e+06 1222.312 > AAC 100.2 0.33 > > However the following command > > dat <- read.table("mydat.txt"); > > print(dat) > > n1 <- sum(as.matrix(dat$V1)); > > gives: > Error in sum(as.matrix(dat$V1)) : invalid 'type' (character) of argument > > > What's wrong with the data type so that it gives such error? > > > - Gundala Viswanath > Jakarta - Indonesia > > ______________________________________________ > 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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.