Question

I have the following matrix:

> dat

       [,1]      [,2]       [,3]        [,4]
foo 0.7574657 0.2104075 0.02922241 0.002705617
foo 0.0000000 0.0000000 0.00000000 0.000000000
foo 0.0000000 0.0000000 0.00000000 0.000000000
foo 0.0000000 0.0000000 0.00000000 0.000000000
foo 0.0000000 0.0000000 0.00000000 0.000000000
foo 0.0000000 0.0000000 0.00000000 0.000000000

and given this:

> new_names <- c("f0","f1","f2","f3","f4","f5");
# where the length of new_names matches the number of rows in the dat matrix

How can I get this?

        [,1]      [,2]       [,3]        [,4]
f0 0.7574657 0.2104075 0.02922241 0.002705617
f1 0.0000000 0.0000000 0.00000000 0.000000000
f2 0.0000000 0.0000000 0.00000000 0.000000000
f3 0.0000000 0.0000000 0.00000000 0.000000000
f4 0.0000000 0.0000000 0.00000000 0.000000000
f5 0.0000000 0.0000000 0.00000000 0.000000000

Answer 1

Maybe something like this?

dat <- matrix(c(c(0.7574657, 0.2104075, 0.02922241, 0.002705617), rep(0, 4*6-4)), ncol = 4, nrow = 6, byrow = TRUE)

rownames(dat) <- paste0("f", seq(0, nrow(dat)-1))

If you already have a vector of names, then

rownames(dat) <- new_names