On Fri, 2010-01-29 at 18:56 +0800, Uwe Dippel wrote: > This is what I tried: > > > num.vec <- c(12.34,56.78,90.12,34.56) > > names(num.vec)<-c("first","second","third","fourth") > > num.vec > first second third fourth > 12.34 56.78 90.12 34.56 > > seq<-(1:4) > > num.mat<-rbind(num.vec,seq) > > num.mat > first second third fourth > num.vec 12.34 56.78 90.12 34.56 > seq 1.00 2.00 3.00 4.00 > > num.vec [3:4] > third fourth > 90.12 34.56 > > (until here I'm fine) > > > num.mat [seq] > [1] 12.34 1.00 56.78 2.00 > > num.mat [num.vec] > [1] NA NA NA NA > > num.vec [seq] > first second third fourth > 12.34 56.78 90.12 34.56 > > num.mat [num.vec] > [1] NA NA NA NA > > num.mat [-seq] > [1] 90.12 3.00 34.56 4.00 > > (and here I'm lost!) > > How could I display a row, instead of always seemingly falling back to > columns?
You're indexing the matrix as if it were a vector. Which is fine, except that in R matrices are indexed by columns, hence the last result your got - you dropped the first 4 entries which are the first two columns, hence you got the last two columns of data. Knowing this you could alter your seq to be seq(1, 8, by = 2): > num.mat[seq(1, 8, by = 2)] [1] 12.34 56.78 90.12 34.56 Thank full there is an easier way: ?`[` has the details, look at arguments i and j. > num.mat[1,] first second third fourth 12.34 56.78 90.12 34.56 or, without the (col)names > unname(num.mat[1,]) [1] 12.34 56.78 90.12 34.56 HTH G > > Uwe > > ______________________________________________ > 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. -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ 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.