Add a footnote citation outside of plot area in R?

Question

I\'d like to add a footnote citation to my 3-panel facet grid plot produced in R. It\'s a footnote to credit the data source. I\'d ideally like to have it below and external t

Answer 1

ggplot2 now has this ability natively with no need for additional packages. ... + labs(caption = "footnote", ...)

library(ggplot2) 
ggplot(diamonds, aes(carat, price, color = clarity)) + 
  geom_point() + 
  labs(title = "Diamonds are forever...", 
       subtitle = "Carat weight by Price", 
       caption = "H. Wickham. ggplot2: Elegant Graphics for Data Analysis Springer-Verlag New York, 2009.")