How to pass aes parameters of ggplot to function

Question

I am using gapminder and trying to write a simple function showing graphs of lifeExp against gdpPercap. However, when I put the arguments in the fu

Answer 1

You need to use tidy evaluation inside aes(). Either .data[[ ]] or {{ }} (curly curly) would work. See also this answer and Tidy evaluation section in Hadley Wickham's Advanced R book.

library(gapminder)
library(rlang)
library(ggplot2)

plotting <- function(input, xx, yy) {
  ggplot(input, aes(.data[[xx]], .data[[yy]], size = pop, color = country)) +
    geom_point(show.legend = FALSE)
}

plotting(gapminder, "lifeExp", "gdpPercap")

plotting2 <- function(input, xx, yy) {
  ggplot(input, aes({{xx}}, {{yy}}, size = pop, color = country)) +
    geom_point(show.legend = FALSE)
}

plotting2(gapminder, lifeExp, gdpPercap)

^{Created on 2019-11-09 by the reprex package (v0.3.0)}