Alternative to if-then-else with logical variables in R

A S Published at Dev

A S

Let's say I have a function, which takes three logical arguments and returns a string indicating which of those were set to TRUE:

func_log <- function(option_1, option_2, option_3) {
    if (option_1 && option_2 && option_3) {
        opt <- "all"
    } else {
        if (option_1 && option_2) {
            opt <- "first two"
        } else {
            if (option_1 && option_3) {
                opt <- "first, last"
            } else {
                opt <- "last two"
            }
        }
    }
return(opt)
}

Is there a way to avoid constructing these if-else here? Using switch may be (would be grateful for an example then)? Any other way?

Frank

How about

myfun <- function(...) which(c(...))

# examples
myfun(TRUE,FALSE,TRUE)
# [1] 1 3
myfun(FALSE,FALSE,TRUE,TRUE,FALSE,TRUE)
# [1] 3 4 6

You could put names on these cases if you wanted to, like

mystrfun <- function(...) toString(c(letters,LETTERS)[myfun(...)])

mystrfun(TRUE,FALSE,TRUE)
# [1] "a, c"
mystrfun(FALSE,FALSE,TRUE,TRUE,FALSE,TRUE)
# [1] "c, d, f"

Replace c(letters,LETTERS) with whatever your desired names are, and they'll get strung together.

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