Naming array dimensions gives error: length of 'dimnames' not equal to array extent

Question

This is my first time using a 3 dimensional array and I am having problems about naming the third dimension.

ReplicateData <- array(0, c(240, 500, 5), dimnames=list(NULL, NULL, c("Returns", "Replicates", "Asset Class")))

I am getting the error:

Length of dimnames not equal to array extent

This seems like it should be a simple issue but I can't find an explicit example in the help docs or online.

Hysteric

Answer 1

The third dimension of your array is of extent 5, but the vector of names for that dimension is of length three.

Hardener

Thanks. I was thinking that the name length should match the number of dimensions. – Hysteric

Well, that's something you can have, too; something we call "named dimnames". The table() function actually is an important example using them: > with(airquality, table(OzHi=Ozone > 80, Month, useNA="ifany")) Month OzHi 5 6 7 8 9 FALSE 25 9 20 19 27 TRUE 1 0 6 7 2 <NA> 5 21 5 5 1 You'd manually use something like tab. <- array(1:15, dim=c(3,5), dimnames= list(OzHi = c("FALSE", "TRUE", NA), Month = c("5", "6", "7", "8", "9"))) to get the "same" [why on earth, can't I get "markdown" to work?] – Bickering

Answer 2

Since I understand answers better with a bit 'o code to guide me... here is Jonathan Chang's correct answer translated to code:

ReplicateData <- array(0,c(240,500,5),dimnames=list(NULL, NULL, 
  c("Returns","Replicates","Asset Class", "Fourth Dimname", "Fifth Dimname")))

Nablus