# Re: [R] an array of matrices

From: jim holtman <jholtman_at_gmail.com>
Date: Mon, 21 May 2007 04:57:40 -0400

Create a matrix of list:

> A = matrix(1:4,2,2)
> B = matrix(1:25,5,5)
> C = matrix(1,3,3)
> D = matrix(1,4,4)
> x <- list(A,B,C,D)
> dim(x) <- c(2,2)

> x[[1,1]]

[,1] [,2]
[1,] 1 3
[2,] 2 4
> x[[2,2]]

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

```[1,]    1    1    1    1
[2,]    1    1    1    1
[3,]    1    1    1    1
[4,]    1    1    1    1

```

On 5/21/07, Scott Hyde <hydes_at_byuh.edu> wrote:
>
>
> I'd like to have a three dimensional array of matrices. I thought I
> could construct a five dimensional array to have the three dimensional array
> of matrices. However, not all of the matrices in the array have the same
> dimensions, which seems to mean I can't use a five dimensional array.
>
> What I'd like is this:
>
> A = matrix(1:4,2,2)
> B = matrix(1:25,5,5)
> C = matrix(1,3,3)
> D = matrix(1,4,4)
>
> I'd like to construct an array for which, if I type F[1,1], it returns
> matrix A, type F[1,2] and it returns B, type F[2,1] and it returns C, or
> type F[2,2] and it returns D.
>
> Essentially, I'd like to be able to access them like they were elements of
> a matrix. Although this example is only a two dimensional array of
> matrices, I'd like it to also work with three dimensions also.
>
> The only thing I thought of to try was to make an array of lists and store
> the matrices inside of an array of lists (where each matrix is stored as a
> list with one item).
>
> Any suggestions?
>
> -Scott
>
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> and provide commented, minimal, self-contained, reproducible code.
>

```--
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

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