Conversion: Can we allow user to provide input for a function in percentages in R?

Question

Question:

I'm wondering how I can define a way such that if a user of a function provided an input value in "percentages" then before using these input values, the function converts these percentages to a corresponding ordinary numeric values to be used in the function?

Note: By percentage as input value, I literally mean a user could put 12.5% or 1.5% etc. and so these values be converted to .125 and .015.

A simple annotated R example is below:

Accept.percent = function(x) {  # "x" can be as small as ".013" & as large as ".85"
                                # but user can provide "1.3%" to "85%"
cdf <- pbeta(x, 4, 2)           # and we can convert the input values
                                # provided as percentages to a corresponding
  return(cdf)                   # ordinary numeric values before use.

}

## Example of use:

Accept.percent(.013)

Answer 1

Sure, you can cut off the % sign, convert to a numeric variable and divide by 100

x2 <- as.numeric(substr(x, 1, nchar(x)-1)) / 100

Then use x2 in your call to pbeta()

Answer 2

Do you need to allow for the percentage sign too? If not, you can do it by adding a condition and a coorespondong argument:

my_fun <- function(x, percentage = FALSE){
  if (percentage) x <- x/100

  (rest of function goes here) 
}