CODEWITHSUNDEEP
rlistmatrix
Hanadulset
Hanadulset

Reputation: 138

Accessing and manipulating list elements in a matrix of lists

I have created a matrix of lists of varying length. The length of the lists is determined by elements in a matrix of the same shape.

I need to access elements of the lists. 

myMatrix <- matrix(list(), nrow=Sims, ncol=Scens)    

for (i in 1:Scens) {      
  for (j in 1:Sims) {
    bin <- list(c(rlnorm(Frequency_matrix[j, i], meanlog=mu[i], sdlog=sigma[i])))
    if (Frequency_matrix[j,i] == 0){
      myMatrix[j, i] <- list(0)
    } else {
      myMatrix[j, i] <- bin
    }
  }
}

The output for element [1, 22] then appears:

[1] 1665085 1444953 1393626 1076812 2187266

and is of list class. However, the list is of length 1. It appears that the list is getting flattened.

I cannot access the elements of this list. I'd expect to be able to access the elements with:

myMatrix[1,22][[2]]

Using this, I aim to apply rank correlations to the matrix based on the sums of the individual list elements. However, I must be able to access each list element individually as well.

Upvotes: 0

Views: 225

Answers (2)

G. Grothendieck
G. Grothendieck

Reputation: 269481

Create plain numeric vectors instead of lists and rather than assigning to myMatrix[i, j] assign to myMatrix[[i, j]] like this:

nr <- 4; nc <- 2
myMatrix <- matrix(list(), nr, nc)
for (i in 1:nr) {
  for (j in 1:nc) {
    myMatrix[[i, j]] <- c(i, j)
  }
}

myMatrix[[3, 2]]
## [1] 3 2

Upvotes: 1

trosendal
trosendal

Reputation: 1234

Try 

myMatrix[1,22][[1]][2]

For the second item in the vector stored in the first list item in the first row and 22nd column of your matrix :)

Upvotes: 0

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