Accessing named members of a list in an array
Your problem is that you are trying to use `$` on an atomic vector rather than a list: > a<- array(list(NULL),dim=c(2,2)) > a[[1,1]] <- c(a=2,b=3) > a[[1,1]]$a Error in a[[1, 1]]$a : $ operator is invalid for atomic vectors > a[[1,1]] a b 2 3 > a[[1,1]] <- list(a=2,b=3) > a[[1,1]]$a [1] 2 > a[[1,1]] $a [1] 2 $b [1] 3 From the description of the problem, perhaps it would be easier to just have a 3-dimensional array. Pat
On 30/06/2012 14:35, mlell08 wrote:
Dear List, I've created a two-dimensional array which shall contain a value and its error, respectively. These two values are concatenated in al list and bear the names "sl" and "sl_err" But I can't adress them using the $-notation. a<- array(list(NULL),dim=c(2,2)) a[[1,1]]<- c(a=2,b=3) a[[1,1]]$a ## Fehler in a[[1, 1]]$a : $ operator is invalid for atomic vectors a[[1,1]]["a"] # This works however. ## a ## 2 I always thought these two methods of indexing are equal? Is there any way to use the $-Style indexing? Thank you, Moritz
Patrick Burns pburns at pburns.seanet.com twitter: @portfolioprobe http://www.portfolioprobe.com/blog http://www.burns-stat.com (home of 'Some hints for the R beginner' and 'The R Inferno')