CODEWITHSUNDEEP
rlist
João Carvalho
João Carvalho

Reputation: 159

Extract entries from a list and store each one on a matrix

Okay, so I have the following list on R:

seg_sites      list[1000]       List of length 1000
 [[1]]       double [40x162]    00000000000000000000000...
 [[2]]       double [40x150]    11110000000000000000000...
 [[3]]       double [40x160]    00000000111111110000000...
 [[4]]       double [40x93]     00110000000000111100000...
 [[5]]       double [40x144]    00000110000000000110000...
  ...

And the list goes on for a thousand entries. As you can see, I always have the same number of rows but I have different number of columns for each entry. What I want to do, is extract each entry to a single matrix. For example, I want to create a matrix called "output_1" containing the information the [[1]] entry, then output_2 with the information from the [[2]] entry and so on.

I was trying to use a for loop for this:

# Loop to intialize the matrices where I want to store the different entries
for(i in 1:nrep) {
     output_single_i <- matrix(data = NA, nrow = 40, ncol = ncol(single[["seg_sites"]][[i]]))
}

# Loop to actually store the different entries in each matrix 
for(i in 1:nrep) {  
  output_single_i <- matrix(single$seg_sites[[i]], ncol = ncol(single[["seg_sites"]][[i]]))
}

What this code is doing is just saving the last entry on the list on a matrix called "output_single_i" but I don't know how to fix it. Any help would be greatly appreciated

Upvotes: 1

Views: 40

Answers (1)

Sathish
Sathish

Reputation: 12723

we can use assign to create matrix data from a list of matrices. The matrix data are saved in global environment, which you can inspect using ls()

invisible( lapply(seq_along(mylist), function(x) {
  assign( x = paste0("Output", x), value = mylist[[x]], envir = .GlobalEnv )
  return(TRUE)
  } ))

Another way is to use list2env() function

names(mylist) <- paste0( 'output', seq_along(mylist))
list2env( mylist, envir = .GlobalEnv)

Data:

mylist <- list(matrix(1:10, ncol = 5), matrix(1:10, ncol = 2))
    str(mylist)
    # List of 2
    # $ : int [1:2, 1:5] 1 2 3 4 5 6 7 8 9 10
    # $ : int [1:5, 1:2] 1 2 3 4 5 6 7 8 9 10

Upvotes: 2

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