[R] Question about range of letters

[Ben Bolker]

Nia Gupta <nia_gupta <at> yahoo.com> writes:

> 
> Hello, 
 
> I have a column with a bunch of letters. I would like to keep some
> of these letters (A,C,D,L) and turn the rest into 'X'.
 
> I have tried using ifelse with '|' in between the argument but it
> didn't work nor did 4 separate ifelse statements.
 
> Example, I currently have:
> Letters    A    B    C    D    E
> I would like to have:
> Letters    A    X    C    D    X
> Thank you

  %in% will be helpful

 Letters <- LETTERS[1:5]
 targets <- c("A","C","D","L")
 Letters[!Letters %in% targets] <- "X"