# [R] Merge list to list - as list

Sun Sep 3 14:28:55 CEST 2006

```Dear all,
#Now I have a dataset with list of list like:
x <- list(list(matrix(1:20, 5, 4),matrix(1:20, 5, 4)),
list(matrix(1:20, 5, 4),matrix(1:20, 5, 4)))
y <- list(list(c(1, -1, -1, 1, 1),c(1, 1, -1, -1, -1)),
list(c(1, 1, 1, 1, 1),c(1, 1, -1, 1, -1)))
x
y

#I need merge x and y, I have tried with
list.uni <- vector("list", length(x))
for (i in 1:length(x)) {
for (j in 1:length(x[[1]])) {
list.uni[[i]][[j]] <- mapply(cbind,
x[[i]][[j]],
y[[i]][[j]],
SIMPLIFY=FALSE)
}
}
list.uni

I have learn about ?lapply, ?sapply and ?mapply but I still didn't
understand how to use it.
I need the result something like

[[1]]
[[1]][[1]]
[,1] [,2] [,3] [,4] [5]
[1,]    1    6   11   16  1
[2,]    2    7   12   17  -1
[3,]    3    8   13   18  -1
[4,]    4    9   14   19  1
[5,]    5   10   15   20  1

[[1]][[2]]
[,1] [,2] [,3] [,4] [5]
[1,]    1    6   11   16  1
[2,]    2    7   12   17  1
[3,]    3    8   13   18  -1
[4,]    4    9   14   19  -1
[5,]    5   10   15   20  -1

[[2]]
[[2]][[1]]
[,1] [,2] [,3] [,4] [5]
[1,]    1    6   11   16  1
[2,]    2    7   12   17  1
[3,]    3    8   13   18  1
[4,]    4    9   14   19  1
[5,]    5   10   15   20  1

[[2]][[2]]
[,1] [,2] [,3] [,4] [5]
[1,]    1    6   11   16  1
[2,]    2    7   12   17  1
[3,]    3    8   13   18  -1
[4,]    4    9   14   19  1
[5,]    5   10   15   20  -1

Thanks you for any help.

#Gabor Grothendieck ggrothendieck at gmail.com
#Mon Aug 28 13:53:52 CEST 2006

Here are two ways:

1. use indexes:

lapply(seq(along = x), function(i) cbind(x[[i]], y[[i]]))

2. use mapply:

mapply(cbind, x, y, SIMPLIFY = FALSE)

On 8/28/06, Muhammad Subianto <msubianto at gmail.com> wrote:
> Dear all,
>
> I have dataset
> x <- list(matrix(1:20, 5, 4),matrix(1:20, 5, 4),matrix(1:20, 5, 4))
> y <- list(matrix(110:114, 5, 1),matrix(110:114, 5, 1),matrix(110:114, 5, 1))
>
> I need merge x and y as list (y put in last column).
> The result is something like
>
> [[1]]
>     [,1] [,2] [,3] [,4]  [,5]
> [1,]    1    6   11   16   110
> [2,]    2    7   12   17   111
> [3,]    3    8   13   18   112
> [4,]    4    9   14   19   113
> [5,]    5   10   15   20   114
>
> [[2]]
>     [,1] [,2] [,3] [,4]  [,5]
> [1,]    1    6   11   16   110
> [2,]    2    7   12   17   111
> [3,]    3    8   13   18   112
> [4,]    4    9   14   19   113
> [5,]    5   10   15   20   114
>
> [[3]]
>     [,1] [,2] [,3] [,4]  [,5]
> [1,]    1    6   11   16   110
> [2,]    2    7   12   17   111
> [3,]    3    8   13   18   112
> [4,]    4    9   14   19   113
> [5,]    5   10   15   20   114
>
> I have tried
> a <- list(x,y)
> as.data.frame(t(sapply(a, rbind)))
> lapply(a, function(x) matrix(unlist(x), nrow = length(x), byrow = TRUE))
> but I don't know how to fix it.
>