ggplot plots in scripts do not display in Rstudio

though it's a quite old question. I had the same problem and found a quick solution, if you want to use "source" button on R studio edit box.

you can simply turn on "source with echo" (Ctrl + Shift + Enter) and the plot shows as expected

The solution is to explicitly call print() on ggplot object:

library(ggplot2)

p <- ggplot(mtcars, aes(wt, mpg))
p <- p + geom_point()
print(p)

ggplot function returns object of class ggplot; ggplot2 works by overloading print function to behave differently on objects of class ggplot - instead of printing them to STDOUT, it creates chart.

Everything is working well in interactive mode, because R assumes that most of commands are run through print() function. This is for our convenience and allows us to type rnorm(1) and get any visible output. When Run current selection command is used (Ctrl+Enter), RStudio behaves as if each selected line was typed in interactive mode and run. You can verify that by checking your command history in Console pane after running few selected lines.

But this convenient mode is abandoned when file is read by source(). Since this function is intended to run (potentially long and computationally-expensive) R scripts, it is undesirable to pollute STDOUT with low-priority messages. That's why source() by default will output only error message. If you want anything else, you have to explicitly ask for that.

I recently happened on this question and realized that the most up to date way is to call show(p) after creating the plot.