suppress NAs in paste()
na, paste, r
Solution
For the purpose of a "true-NA": Seems the most direct route is just to modify the value returned by `paste2` to be `NA` when the value is `""`
paste3 <- function(...,sep=", ") {
L <- list(...)
L <- lapply(L,function(x) {x[is.na(x)] <- ""; x})
ret <-gsub(paste0("(^",sep,"|",sep,"$)"),"",
gsub(paste0(sep,sep),sep,
do.call(paste,c(L,list(sep=sep)))))
is.na(ret) <- ret==""
ret
}
val<- paste3(c("a","b", "c", NA), c("A","B", NA, NA))
val
#[1] "a, A" "b, B" "c" NA
Problem
Regarding the bounty Ben Bolker's `paste2`-solution produces a `""` when the strings that are pasted contains `NA`'s in the same position. Like this, ``` > paste2(c("a","b", "c", NA), c("A","B", NA, NA)) [1] "a, A" "b, B" "c" "" ``` The fourth element is an `""` instead of an `NA` Like this, ``` [1] "a, A" "b, B" "c" NA ``` I'm offering up this small bounty for anyone who can fix this. Original question I've read the help page `?paste`, but I don't understand how to have R ignore `NA`s. I do the following, ``` foo <- LETTERS[1:4] foo[4] <- NA foo [1] "A" "B" "C" NA paste(1:4, foo, sep = ", ") ``` and get ``` [1] "1, A" "2, B" "3, C" "4, NA" ``` What I would like to get, ``` [1] "1, A" "2, B" "3, C" "4" ``` I could do like this, ``` sub(', NA$', '', paste(1:4, foo, sep = ", ")) [1] "1, A" "2, B" "3, C" "4" ``` but that seems like a detour.