[R] conversion of matrix into list

[Norm Matloff]

Martin Spindler wrote:

> I have a matrix X which consists of 2 columns. I would like to convert this
> matrix into a list where every entry of the list consists of a single row of
> the matrix.

Here's another way besides split():

# returns a list of the matrix m's rows (rowcol=1) or columns
mat2lst <- function(m,rowcol=1) {
   if (rowcol == 1) m <- t(m)
   dm <- as.data.frame(m)
   as.list(dm)
}

This seems to be faster than the split() approach for columns, but
slower for rows.  Apparently the transpose operation makes the
difference.  (You could try investigating via Rprof().)

Norm Matloff