how to rename a variable using a dynamic name and dplyr?

Question

I want to rename a column inside a function with a name passed as an argument for this function. Basically, I have a function

produce_data_frame <- function(name) {
  return(iris)
}

And I want that this function change the Sepal.length column name with 'name' (with name taking the value of name) I tried different things such as

produce_data_frame <- function(name) {
  name <- enquo(name)
  iris %>%
    rename((!!name) = Sepal.Length) %>%
    return()
}

And when calling

produce_data_frame("newName")

I would like to get back the iris data.frame with the Sepal.Length column named newName. But my understanding of NSE is still very basic, and it doesn't even compile.

Answer 1

You can try

library(tidyverse)

produce_data_frame <- function(name) {
  iris %>%
    as.tibble() %>% 
    select(!!quo_name(name) := Sepal.Length)
}

produce_data_frame("new_name")
#> # A tibble: 150 x 1
#>    new_name
#>       <dbl>
#>  1     5.10
#>  2     4.90
#>  3     4.70
#>  4     4.60
#>  5     5.00
#>  6     5.40
#>  7     4.60
#>  8     5.00
#>  9     4.40
#> 10     4.90
#> # ... with 140 more rows

Created on 2018-04-04 by the reprex package (v0.2.0).

Or you can use{{...}}

produce_data_frame <- function(name) {
  iris %>%
    as_tibble() %>% 
    select({{name}} := Sepal.Length)
}