CODEWITHSUNDEEP
rlapply
rxk011
rxk011

Reputation: 107

Concatinating two different size of lists in R

I have two lists of matrices, LIST1 (size m), and LIST2(size n). Each matrix of LIST1 is size (p,q) and LIST2 contains column matrices of size (p,1). I want to combine each of LIST2 column matrices to each LIST1. I tried lapply, but couldn't figure that out. The size of the output list is mn

Upvotes: 1

Views: 71

Answers (1)

akuiper
akuiper

Reputation: 214957

You can make a nested loop with lapply:

unlist(lapply(LIST1, function(x) lapply(LIST2, cbind, x)), recursive = F)

Here is a small reproducible example:

LIST1 <- list(matrix(1:4, nrow = 2), matrix(2:5, nrow = 2))
LIST2 <- list(matrix(1:2, nrow = 2))
unlist(lapply(LIST1, function(x) lapply(LIST2, cbind, x)), recursive = F)

#[[1]]
#     [,1] [,2] [,3]
#[1,]    1    1    3
#[2,]    2    2    4

#[[2]]
#     [,1] [,2] [,3]
#[1,]    1    2    4
#[2,]    2    3    5

Upvotes: 3

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