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I have a strange issue with Rstudio: If a script calls ggplot2 functions to display a plot, then using Source to run the script does not produce the plots. If I select the whole script with Ctrl+A, then Run the current line or selection (Ctrl+Enter), then the plot does display. Likewise, typing plotting commands into the console produces correct output.

For example:

library(ggplot2)

p = ggplot(mtcars, aes(wt, mpg))
p + geom_point()

Will only produce output if pasted into console, not if sourced.

There are other questions about this, but neither is helpful:

How can I get Rstudio to display plots when a script is sourced? I am using Rstudio 0.98.1062 and R 3.1.1.

Community
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Superbest
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5 Answers5

154

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.

Mirek Długosz
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    Jesus... I hate how all these tutorial sites don't even mention you have to call print. So stupid. Source: https://datacarpentry.org/R-ecology-lesson/04-visualization-ggplot2.html – NoName Jun 09 '21 at 03:39
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    @NoName I am in total agreement with you. Also, I disagree with the design specification that makes "print" necessary in the first place. – Peter Leopold Aug 02 '22 at 16:57
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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

bcat
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    Great, didn't knew that! That adds nicely to the explanation given by @Mirosław Zalewski. – Uwe Oct 01 '16 at 07:31
12

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

Superbest
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  • Do you have any sources that this is the most up to date way? All I can find is this: https://ggplot2.tidyverse.org/reference/print.ggplot.html – Chris Jul 17 '19 at 08:26
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I found this question when searching a similar problem (plots not showing up in RStudio). I was trying to troubleshoot a complicated ggplot2 block by running it in parts, but couldn't get anything to show up in the plot window.

Reason: the tiff() function I opened earlier had not closed.

Solution: I ran dev.off() a few times until all my earlier tiff() functions completed, then I was able to create plots in RStudio and view the results in the plot window.

Tania
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0

Another option is simply using plot(). When clicking on "Source" in Rstudio, it show the plot in the window like this:

library(ggplot2)

p = ggplot(mtcars, aes(wt, mpg))
p = p + geom_point()
plot(p) 

# This pops when clicking on Source
source("~/.active-rstudio-document")

Output:

enter image description here

Quinten
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