Hello! let: test<-1:3 list(test) names(test)<-c("X11","X12","Y23") >test[["Y2"]] 3 I had assumed that the names in a list are like a keys in a hash. Therefore i thought that no value should be returned. The behavior of: >test["Y2"] <NA> NA is as i expected. Should it be as it is? How is the definition of [[]] and []? /Eryk