On Apr 6, 2010, at 6:39 AM, Robert M. Flight wrote: > Hi All, > > I'm hoping someone else can help me out with this. I am doing some > matrix algebra using sub-parts of matrices, and sometimes I need only > a single row/column of the original matrix. However, whenever I pull > out only a single row/column, R returns a row vector, but often this > will break my matrix algebra. Is there any *easy* way to get R to > remember what the single row/column came out of and format the return > appropriately? > > Example: > > crud <- matrix(c(1,2,3,4,5,6,7,8,9,10,11,12),nrow=3,ncol=4) > tmp <- crud[,1] > #tmp gives: [1] 1 2 3 > > what I actually want is: > tmp <- crud[,1] > #tmp gives > [,1] > [1,] 1 > [2,] 2 > [3,] 3 > > I don't see an easy way to do this beyond using matrix and supplying > the correct matrix dimensions based on the indexing, or using a > conditional to check if only one column/row is being taken out. > > Any help would be very much appreciated. > > Regards, > > -Robert
See R FAQ 7.5: http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-do-my-matrices-lose-dimensions_003f HTH, Marc Schwartz ______________________________________________ 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.
