Check if R is running in RStudio

This is from ?rstudio:

# Test whether running under RStudio 
isRStudio <- Sys.getenv("RSTUDIO") == "1"

There is also rstudioapi::isAvailable(), but checking this is not as reliable because RStudio doesn't seem to really need the rstudioapi package to work correctly.

Check the .Platform$GUI option for "RStudio"

is.rstudio = function(){
  .Platform$GUI == "RStudio"
}

See:

http://thecoatlessprofessor.com/programming/detecting-if-r-is-in-rstudio-and-changing-rstudios-default-graphing-device/