Create a list from a big matrix in R

Question

I'm trying to create a list from a big matrix as following:

  A = matrix(rnorm(500000*10), nrow = 500000, ncol = 10)
    B = list()
    begin = Sys.time()
    for (i in 1: nrow(A)){
      B[[i]] = A[i,]
    }
    end = Sys.time()
    end - begin

However it takes too much time. Any idea to optimize this code? Thank you.

score 0 · Answer 1 · answered Aug 20 '15 at 14:32

0

Sweet and simple

B = as.list(data.frame(t(A)))

answered Aug 20 '15 at 14:32

Sidhha

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Create a list from a big matrix in R

1 Answers1