I have a function which takes a column name as an input:
library(tidyverse)
dat <- diamonds
ex_func <- function(df, grp) {
df %>%
distinct(cut, get(grp))
}
ex_func(dat, grp = "color")
How exactly do I get the name of the second column in the resulting group to be the input (e.g. "color", rather than get(grp))?
If we are using both unquoted or quoted value, then use ensym and evaluate (!!)
library(dplyr)
ex_func <- function(df, grp) {
df %>%
distinct(cut, !! rlang::ensym(grp))
}
-testing
ex_func(dat, "color")
# A tibble: 35 x 2
# cut color
# <ord> <ord>
# 1 Ideal E
# 2 Premium E
# 3 Good E
# 4 Premium I
# 5 Good J
# 6 Very Good J
# 7 Very Good I
# 8 Very Good H
# 9 Fair E
#10 Ideal J
# … with 25 more rows
ex_func(dat, color)
# A tibble: 35 x 2
# cut color
# <ord> <ord>
# 1 Ideal E
# 2 Premium E
# 3 Good E
# 4 Premium I
# 5 Good J
# 6 Very Good J
# 7 Very Good I
# 8 Very Good H
# 9 Fair E
#10 Ideal J
# … with 25 more rows
If we prefer to use only unquoted, the option is {{}}
ex_func <- function(df, grp) {
df %>%
distinct(cut, {{grp}})
}