Let the matrices A and B.
A=c(1:5)*matrix(1,5,5)
B=10*A
that is,
> A
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 1 1 1
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
> B
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 20 20 20 20 20
[3,] 30 30 30 30 30
[4,] 40 40 40 40 40
[5,] 50 50 50 50 50
I would like, for example, to switch the first rows between the matrices A and B, that is
> A
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
> B
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 1 1 1
[2,] 20 20 20 20 20
[3,] 30 30 30 30 30
[4,] 40 40 40 40 40
[5,] 50 50 50 50 50
using a function, and without using any indermediate vector or a for loop.
As per you update in the comment, you can try
lapply(
1:nrow(B),
function(k) {
setNames(
Map(
function(x, ind,r) {
x[ind, ] <- r
x
},
list(A, B),
list(1,k),
list(B[k, ], A[1, ])
), c("A", "B")
)
}
)
which gives
[[1]]
[[1]]$A
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
[[1]]$B
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 1 1 1
[2,] 20 20 20 20 20
[3,] 30 30 30 30 30
[4,] 40 40 40 40 40
[5,] 50 50 50 50 50
[[2]]
[[2]]$A
[,1] [,2] [,3] [,4] [,5]
[1,] 20 20 20 20 20
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
[[2]]$B
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 1 1 1 1 1
[3,] 30 30 30 30 30
[4,] 40 40 40 40 40
[5,] 50 50 50 50 50
[[3]]
[[3]]$A
[,1] [,2] [,3] [,4] [,5]
[1,] 30 30 30 30 30
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
[[3]]$B
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 20 20 20 20 20
[3,] 1 1 1 1 1
[4,] 40 40 40 40 40
[5,] 50 50 50 50 50
[[4]]
[[4]]$A
[,1] [,2] [,3] [,4] [,5]
[1,] 40 40 40 40 40
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
[[4]]$B
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 20 20 20 20 20
[3,] 30 30 30 30 30
[4,] 1 1 1 1 1
[5,] 50 50 50 50 50
[[5]]
[[5]]$A
[,1] [,2] [,3] [,4] [,5]
[1,] 50 50 50 50 50
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
[[5]]$B
[,1] [,2] [,3] [,4] [,5]
[1,] 10 10 10 10 10
[2,] 20 20 20 20 20
[3,] 30 30 30 30 30
[4,] 40 40 40 40 40
[5,] 1 1 1 1 1
You can try the code below
list2env(
setNames(
Map(
function(x, r) {
x[1, ] <- r
x
},
list(A, B),
list(B[1, ], A[1, ])
), c("A", "B")
),
envir = .GlobalEnv
)