Shiny: passing input$var to aes() in ggplot2

Question

I am trying to write a Shiny app graphing the density of a variable VAL, by categories of age (AGE) or sex (SEX). The user selects \"SEX\" or \"AGE\" in the dropdown menu, a

Answer 1

I'm not sure this is still an open question, but an alternative to the aes_string would be to convert the string to a symbol:

library(ggplot2)

# usually you can put all the shared aesthetics in the first line
ggplot(mtcars, aes(mpg, hp, colour = cyl)) +
  geom_point()

# when the input is a string, you can use aes_string(), but you'd
# have to enter the string var separately, or change all vars..

input <- "cyl"

ggplot(mtcars, aes(mpg, hp)) +
  geom_point(aes_string(colour = input))

# or
# ggplot(mtcars, aes_string("mpg", "hp", colour = input)) +
#  geom_point()

# you can put the converted string var in the normal aes()
ggplot(mtcars, aes(mpg, hp, colour = !!as.symbol(input))) +
  geom_point()

# note: as.name() and as.symbol() are aliases

Created on 2018-11-05 by the reprex package (v0.2.0).