transform a matrix wtih 2 columns into a multimap
- by Derek
Hi,
I am wondering if there is a way to transform a matrix of 2 column into a multimap or list of list.
The first column of the matrix is an id (with possibly duplicated entries) and the 2nd column is some value.
For example,
if I have to following matrix
m<-matrix(c(1,2,1,3,2,4), c(3,2))
i would like to transform it into the following list
[[1]]
3,4
[[2]]
2
Thanks,
Derek