Switch Statement with repeated commands in R

Question

In R, is there a way to make a switch statement such that the same block of code is executed for two different cases? Obviously I could copy and paste the whole body of code for both statements, but I was hoping there would be a neater way to do it.

I could also use an if-else block to avoid the repetition of large blocks of code but switches are generally faster in R.

It seems unlikely due to the way R parses a switch statement as a function, but I'm hoping that the developers of R took special care in parsing a switch statement to allow for multiple arguments to refer to the same block of code.

Answer 1

Provide named arguments without values, they fall through to the next expression with value

> switch("A", A=, B=, C="A OR B OR C", "Other")
[1] "A OR B OR C"
> switch("C", A=, B=, C="A OR B OR C", "Other")
[1] "A OR B OR C"
> switch("D", A=, B=, C="A OR B OR C", "Other")
[1] "Other"

This is described on the help page ?switch

 If 'EXPR' evaluates to a character string then that string is
 matched (exactly)to the names of the elements in '...'.  If there
 is a match then that element is evaluated unless it is missing, in
 which case the next non-missing element is evaluated, so for
 example 'switch("cc", a = 1, cc =, cd =, d = 2)' evaluates to '2'.