Several R vs S-Plus issues
Thomas Lumley writes:
On Thu, 4 Oct 2001, Kurt Hornik wrote:
David Brahm writes:
- LETTERS[c(NA,2)] in S is c("","B"), but in R is c("NA","B")
I think we do not want to change this. Splus has
(1:2)[c(NA,2)]
[1] NA 2
is.na((1:2)[c(NA,2)])
[1] T F
is.na(c(TRUE, FALSE)[c(NA,2)])
[1] T F
I think we do want to change this (as we discussed quite recently) but by adding a genuine character NA. The problem is not that LETTERS[c(NA,2)] returns a missing value, it's that it isn't missing enough. We need a "NaS" (Not a String) value that can't be confused with Nabisco, but also can't be confused with an empty string.
Agreed. As Peter said, subscripting by NA should give NA but R cannot distinguish a string NA from the string NA. However, David (I think) was suggesting that subscripting a string with NA should give an empty string, which I think cannot be right. It must be NaS in your sense. -k -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._