R convert matrix or data frame to sparseMatrix

Question

I have a regular matrix (non-sparse) that I would like to convert to a sparseMatrix (using the Matrix package). Is there a function to do this or

Answer 1

For the matrix, someone already has an answer.

For the data.table, there is a package did the job.

library(Matrix)
library(mltools)
x = data.table()
sparseM <- sparsify(x)