在 R 函数中将对象分配给 arguments - 开关，if else 语句或函数？

Question

I am new to R and programming in general and am trying to write a very basic function where the input is 2 numbers and a selection from one of 3 operations. The output is supposed to be the result of a further calculation (divide the result of the input by 3*pi) and then a character string to confirm what operation was selected/performed. I want the default operation to be addition.

I've read up a little on the switch function and if... else type statements but not sure what is the most efficient way to achieve what I am trying to do and so far I haven't been able to get anything to work anyway. I seem to be getting a massive matrix as the output or an error to say I can't return multiple arguments in my current attempt. Can someone help with where I am going wrong? Thank you in advance.

basiccalc <- function(x, y, operation = addition){

addition <- x + y

subtraction <- x - y

multiplication <- x * y

calculation <- operation/(3*pi)

return(calculation, "operation")
}

Answer 1

switch would be useful

basiccalc <- function(x, y, operation = addition) {
   operation <- deparse(substitute(operation))
   op <- switch(operation,
        addition = x + y,
        subtraction = x - y,
        multiplication = x * y)
   return(op/(3 *pi))
}

-testing

> basiccalc(3, 5)
[1] 0.8488264
> 8/(3 * pi)
[1] 0.8488264
> basiccalc(3, 5, operation = subtraction)
[1] -0.2122066   
> (3- 5)/(3 * pi)
[1] -0.2122066