CODEWITHSUNDEEP
rloopsmatrix
Ang
Ang

Reputation: 25

How to create loops for random matrices

I'm trying to create a loop so I can create 1000 random 2x2 matrices (in the range between -10 to 10)

so far I have

M = matrix(c(z = runif(4,min = -10, max = 10)),
           nrow = 2, ncol = 2, byrow = TRUE)

I tried to use k=1000

for (i in 1:k) {
  if (i>=0) print (i) else (print(-i)
}

Upvotes: 0

Views: 177

Answers (1)

Cettt
Cettt

Reputation: 11981

You don't need for.loops to achieve that. You can do so by using lapply. This way you create a list containing the matrices:

set.seed(1)
lapply(1:3, function(z) matrix(runif(4, min = -10, max = 10), nrow = 2, ncol = 2))
[[1]]
          [,1]     [,2]
[1,] -4.689827 1.457067
[2,] -2.557522 8.164156

[[2]]
          [,1]     [,2]
[1,] -5.966361 8.893505
[2,]  7.967794 3.215956

[[3]]
          [,1]      [,2]
[1,]  2.582281 -5.880509
[2,] -8.764275 -6.468865

In order to create 1000 matrices use 1:1000 instead of 1:3.

If you insist on using a loop you can use Markus' solution from the comments:

k <- 1000
out <- vector("list", length = k)
set.seed(1)
for (i in 1:k) { 
  out[[i]] <- matrix(runif(4, min = -10, max = 10), nrow = 2, ncol = 2) 
}
out

Upvotes: 1

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