In the 3 Dimensional array bellow :
ar <- array(someData, c(5, 5, 5));
rownames(ar) <- ...; #to set up row names
colnames(ar) <- ...; #to set up col names
How can i set the third dimension names ?
2 Answers
You can either set the dimnames argument when defining the array:
ar <- array(data = 1:27,
dim = c(3, 3, 3),
dimnames = list(c("a", "b", "c"),
c("d", "e", "f"),
c("g", "h", "i")))
and/or you can set the dimnames of the third dimension like so:
dimnames(ar)[[3]] <- c("G", "H", "I")
Still starting in R but I found this way that may be useful for large multidimensional array.
Instead of naming each of the indexes ('a','b','c','d',....), you can use provideDimnames() function to automatic generate the index names following the pattern you choose.
Creating data
ar <- array (data = 1:(4*3*2) , dim=c(4,3,2))
> ar
, , 1
[,1] [,2] [,3]
[1,] 1 5 9
[2,] 2 6 10
[3,] 3 7 11
[4,] 4 8 12
, , 2
[,1] [,2] [,3]
[1,] 13 17 21
[2,] 14 18 22
[3,] 15 19 23
[4,] 16 20 24
Labelling dimensions
ar <- provideDimnames(ar , sep = "_", base = list('row','col','lev'))
And you get
> ar
, , lev
col col_1 col_2
row 1 5 9
row_1 2 6 10
row_2 3 7 11
row_3 4 8 12
, , lev_1
col col_1 col_2
row 13 17 21
row_1 14 18 22
row_2 15 19 23
row_3 16 20 24
