I have a list of which consists of list of matrices as follows:
$A
$A[[1]]
$A[[1]][[1]]
[,1] [,2]
[1,] 1 6
[2,] 2 7
[3,] 3 8
[4,] 4 9
[5,] 5 10
$A[[2]]
$A[[2]][[1]]
[,1] [,2]
[1,] 2 7
[2,] 3 8
[3,] 4 9
[4,] 5 10
[5,] 6 11
$B
$B[[1]]
$B[[1]][[1]]
[,1] [,2]
[1,] 11 16
[2,] 12 17
[3,] 13 18
[4,] 14 19
[5,] 15 20
$B[[2]]
$B[[2]][[1]]
[,1] [,2]
[1,] 12 17
[2,] 13 18
[3,] 14 19
[4,] 15 20
[5,] 16 21
$C
$C[[1]]
$C[[1]][[1]]
[,1] [,2]
[1,] 0 0
[2,] 0 0
[3,] 0 0
[4,] 0 0
[5,] 0 0
$C[[2]]
$C[[2]][[1]]
[,1] [,2]
[1,] 0 0
[2,] 0 0
[3,] 0 0
[4,] 0 0
[5,] 0 0
The above list of matrices was created using the codes below:
A_mat1 <- matrix(as.numeric(c(1:10)), nrow = 5, ncol = 2)
B_mat1 <- matrix(as.numeric(c(11:20)), nrow = 5, ncol = 2)
C_mat1 <- matrix(as.numeric(0), nrow = 5, ncol = 2)
A_mat2 <- matrix(as.numeric(c(2:11)), nrow = 5, ncol = 2)
B_mat2 <- matrix(as.numeric(c(12:21)), nrow = 5, ncol = 2)
C_mat2 <- matrix(as.numeric(0), nrow = 5, ncol = 2)
my_matrix_name <- as.vector(c("A_mat1", "B_mat1", "C_mat1", "A_mat2", "B_mat2", "C_mat2"))
my_list = list(A_mat1, B_mat1, C_mat1, A_mat2, B_mat2, C_mat2)
names(my_list) <- my_matrix_name
my_A <- as.vector(my_matrix_name[substring(my_matrix_name,1,1) == "A"])
my_B <- as.vector(my_matrix_name[substring(my_matrix_name,1,1) == "B"])
my_C <- as.vector(my_matrix_name[substring(my_matrix_name,1,1) == "C"])
A = list()
for(i in seq_len(length(my_A))){
A[[i]] <- list(my_list[[paste0(my_A[[i]])]])
}
B = list()
for(i in seq_len(length(my_B))){
B[[i]] <- list(my_list[[paste0(my_B[[i]])]])
}
C = list()
for(i in seq_len(length(my_C))){
C[[i]] <- list(my_list[[paste0(my_C[[i]])]])
}
my_group = list(A,B,C)
names(my_group) <- c("A", "B", "C")
my_group
Where group C matrices have values of 0. Now I want to create a formula to overwrite group C equals to group A minus group B i.e. C = A - B
I have tried using
my_group[[3]] = my_group[[1]] - my_group[[2]]
and
my_group[[3]] = Map("-", my_group[[1]] , my_group[[2]])
but it gives error message: non-numeric argument to binary operator. Can anyone help me please? Thanks!
Because you have nested lists, your Map function is actually trying to subtract a list from another list. You need your mapping function to extract the first element of each list and subtract those
Map(function(A, B) A[[1]] - B[[1]], my_group$A , my_group$B)
#> [[1]]
#> [,1] [,2]
#> [1,] -10 -10
#> [2,] -10 -10
#> [3,] -10 -10
#> [4,] -10 -10
#> [5,] -10 -10
#>
#> [[2]]
#> [,1] [,2]
#> [1,] -10 -10
#> [2,] -10 -10
#> [3,] -10 -10
#> [4,] -10 -10
#> [5,] -10 -10