Creating a three dimensional array from a data frame in R

Question

I have radar data in a 2D data frame with 3600 rows and 800 columns that I need to convert to a 3D array with 10 rows, 360 columns, and 800 levels. I need to split the 3600 rows into 10 groups of 360 and convert the 800 columns into the levels for the new array. So, instead of-

> dim(REF)
[1] 3600  800

I need to put the values into the form-

> dim(ref.array)
[1]  10 360 800

I know this is a pretty basic request, but I can't remember much because I haven't used R much since I took the class two years ago. Any help would be appreciated.

Edit to answer questions below.

If we take the example that @BondedDust used, we get the following-

d <- as.data.frame( matrix( 1:(3*4*5), 12, 5))
array( unlist(d), dim=c(3, 4, 5) ) 

, , 1

      [,1] [,2] [,3] [,4]
[1,]    1    4    7   10
[2,]    2    5    8   11
[3,]    3    6    9   12

, , 2

      [,1] [,2] [,3] [,4]
[1,]   13   16   19   22
[2,]   14   17   20   23
[3,]   15   18   21   24

, , 3

      [,1] [,2] [,3] [,4]
[1,]   25   28   31   34
[2,]   26   29   32   35
[3,]   27   30   33   36

, , 4

      [,1] [,2] [,3] [,4]
[1,]   37   40   43   46
[2,]   38   41   44   47
[3,]   39   42   45   48

, , 5

         [,1] [,2] [,3] [,4]
[1,]   49   52   55   58
[2,]   50   53   56   59
[3,]   51   54   57   60

What I'm looking for is an array organized like this-

, , 1

      [,1] [,2] [,3] [,4]
[1,]    1    2    3   4
[2,]    5    6    7   8
[3,]    9    10   11  12

, , 2

      [,1] [,2] [,3] [,4]
[1,]   13   14   15   16
[2,]   17   18   19   20
[3,]   21   22   23   24

, , 3

      [,1] [,2] [,3] [,4]
[1,]   25   26   27   28
[2,]   29   30   31   32
[3,]   33   34   35   36

, , 4

      [,1] [,2] [,3] [,4]
[1,]   37   38   39   40
[2,]   41   42   43   44
[3,]   45   46   47   48

, , 5

      [,1] [,2] [,3] [,4]
[1,]   49   50   51   52
[2,]   53   54   55   56
[3,]   57   58   59   60

Answer 1

Wouldn't this do it?

 new.arr <- array( unlist(dfrm), dim=c(10, 360, 800) ) )

This is what I understood to be the task, but if it is not, then there is an aperm function in the 'aperm' package that will allow "permuting" the dimensions:

d <- as.data.frame( matrix( 1:(3*4*5), 12, 5))
array( unlist(d), dim=c(3, 4, 5) ) 

##=========result============##
, , 1

     [,1] [,2] [,3] [,4]
[1,]    1    4    7   10
[2,]    2    5    8   11
[3,]    3    6    9   12

, , 2

     [,1] [,2] [,3] [,4]
[1,]   13   16   19   22
[2,]   14   17   20   23
[3,]   15   18   21   24

, , 3
snipped rest of output

Since it is now clear that you did want the array equivalent of byrow=TRUE (which is not an option in the R array function), then this provides the desired result:

 aperm( array( unlist(d), dim=c(4, 3, 5) ) , c(2,1,3) )
#===============
, , 1

     [,1] [,2] [,3] [,4]
[1,]    1    2    3    4
[2,]    5    6    7    8
[3,]    9   10   11   12

, , 2

     [,1] [,2] [,3] [,4]
[1,]   13   14   15   16
[2,]   17   18   19   20
[3,]   21   22   23   24

Snipped rest of output.

I was mistaken about aperm being in a different package.