In ggplot, how to set plot title as x variable choosed when using a function

Question

I have a function that when I choose the variables it plots me a ggplot.

It works well.

gg_f <- function(df, var_x){

  ggplot(df, aes(x = {{var_x}}, mpg)) + geom_point()

}

gg_f(df = mtcars, var_x = cyl)

But when I tried to set the plot title as the var_x variable that I choose I have problems.

I tried o use glue but it didnt work:

gg_f <- function(df, var_x){
    
    ggplot(mtcars, aes(x = {{var_x}}, mpg)) + geom_point() + labs(title = glue::glue({var_x})
    
}

How can I do this?

Answer 1

You can use substitute(var_x)

library(ggplot2)

gg_f <- function(df, var_x){

  ggplot(df, aes(x = {{var_x}}, mpg)) + 
    geom_point() +
    labs(title = substitute(var_x))

}

gg_f(df = mtcars, var_x = cyl)

Or rlang::englue:

library(ggplot2)

gg_f <- function(df, var_x){

  ggplot(df, aes(x = {{var_x}}, mpg)) + 
    geom_point() +
    labs(title = rlang::englue("{{var_x}}"))

}

gg_f(df = mtcars, var_x = cyl)

^{Created on 2022-04-10 by the reprex package (v2.0.1)}