On 09/19/2010 10:02 AM, h...@wiseadvice.eu wrote:
Good morning experts! situation: class(myMatrix)="matrix" class(myMatrix[(1:2),]))="matrix" class(myMatrix[1,])= "character" consequences are far reaching as, for instance colnames(myMatrix[(1:2),]) != colnames(myMatrix[1,]) or names(myMatrix[(1:2),]) != names(myMatrix[1,]) My question: 1. How can the coercion to character be avoided and the attributes of the original object myMatrix of class "matrix" been preserved when slicing out one row of the matrix? 2. Is there a reason why there is a "loss of generality" in that sense that a matrix of dimension (1xn) is treated differently than a matrix of dimension (mxn); m,n>1 ? in other words is there a reason why class vector is needed at all?
m <- matrix(1:4, 2) m[1,, drop = FALSE] # [,1] [,2] # [1,] 1 3 m[, 1, drop = FALSE] # [,1] # [1,] 1 # [2,] 2 See ?Extract HTH, Tobias ______________________________________________ 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.
