Keeping the the name of the vector element in the output

Question

My foo function below works great, however it omits the name associated with its vector output.

For the example below, I expect foo to return:

    scale
[1] 2

But it simply returns:

[1] 2

Is there fix for this?

library(tidyverse)
library(rlang)

txt = "
study scale
1     1
1     1
2     2
3     2
3     2
3     2
4     1
"
h <- read.table(text = txt,h=T)

foo <- function(data, ...){

  dot_cols <- rlang::ensyms(...)
  str_cols <- purrr::map_chr(dot_cols, rlang::as_string)
  
min(sapply(str_cols, function(i) length(unique(data[[i]]))))
 
}

foo(h, study, scale)

Answer 1

We may use which.min to get the index and then use it to subset the element. Also, loop over a named vector

foo <- function(data, ...){

  dot_cols <- rlang::ensyms(...)
  str_cols <- purrr::map_chr(dot_cols, rlang::as_string)
  
  v1 <- sapply(setNames(str_cols, str_cols), 
        function(i) length(unique(data[[i]])))
  v1[which.min(v1)]
 
}

-testing

>  foo(h, study, scale)
scale 
    2