1-dimensional Matrix is changed to a vector in R
matrix, r, rcpp, vector
Solution
This is an R FAQ. You need to do `a[3,,drop = FALSE]`.
Problem
``` > a<-matrix(c(1:9),3,3) > a [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 > a[3,]*a[,3] # I expect 1x1 matrix as result of this. [1] 21 48 81 > class(a) [1] "matrix" > class(a[3,]) [1] "integer" ``` In R, 1-dimensional matrix is changed to a vector. Can I avoid this? I would like to keep 1-D matrix as a matrix. Actually, I need to throw many kind of matrix to RcppArmadillo, even zero-D matrix. Changing matrix to vector by itself is my problem.