I have two matrices of arbitrary sizes, e.g. matrix 1 (n * m) and matrix 2 (k * l). Is there a (convenient) way in R to cbind them row-by-row, to form a (n * k) * (m + l) matrix where each row of matrix 1 has a chance to be cbinded to each row of matrix 2? It is a complete row-by-row combination so the order does not matter.
For example, is there a function f such that:
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Thanks!
In the future, please include example data that is copy/pasteable, not just a picture.
m1 = matrix(1:6, ncol = 2)
m2 = matrix(7:12, ncol = 3)
combos = expand.grid(1:nrow(m1), 1:nrow(m2))
cbind(m1[combos$Var1, ], m2[combos$Var2, ])
# [,1] [,2] [,3] [,4] [,5]
# [1,] 1 4 7 9 11
# [2,] 2 5 7 9 11
# [3,] 3 6 7 9 11
# [4,] 1 4 8 10 12
# [5,] 2 5 8 10 12
# [6,] 3 6 8 10 12
There might be a better solution, but this works for smaller size problems:
A <- matrix(c(1,2,3,2,3,4), nrow = 3)
B <- matrix(c(5,6,6,7,7,8), nrow = 2)
temp <- lapply(1:nrow(A), function(x){
C = apply(B, 1, function(y){
c(A[x,],y)
})
return(t(C))
})
output <- do.call(rbind, temp)
cbind(A[rep(1:(x<-nrow(A)),each=y<-nrow(B)),],B[rep(1:y,x),])
[,1] [,2] [,3] [,4] [,5]
[1,] 1 2 5 6 7
[2,] 1 2 6 7 8
[3,] 2 3 5 6 7
[4,] 2 3 6 7 8
[5,] 3 4 5 6 7
[6,] 3 4 6 7 8
x=nrow(A)
y=nrow(B)
cbind(A[rep(1:x,each=y),],B[rep(1:y,x),])
