search for: backaward

Sometimes the absence of a name is maked by an NA: x <- 1:2 names(x)[[1]] <- "a" names(x) # [1] "a" NA Whereas other times its y <- c(a = 1, 2) names(y) # [1] "a" "" Is this deliberate? The help for names() is a bit murky, but an example shows the NA behaviour. Hadley -- http://had.co.nz/

...fact that character-NA is a relative latecomer to the language. In the beginning, there was no real distinction between NA and "NA", causing issues when abbreviating Noradrenaline, North America, Nelson Anderson, etc. At some point, it was decided to fix things up, as far as possible in a backawards compatible way. Some common idioms were retained but others were changed to comply with the rules for other vector types. We have the empty string convention on (AFAICT) all constructor usages: c(a=1, 3) list(a=1, 3) cbind(a=1, 3) and also in the lists implied by argument matching > f <...