我已经从这个页面尝试了所有四个源代码块：https : //orgmode.org/worg/org-contrib/babel/languages/ob-doc-R.html
* does /not/ produce a file
#+begin_src R :file 1.png :results value graphics
library(lattice)
xyplot(1:10 ~ 1:10)
#+end_src
* does produce a file, by printing object
#+begin_src R :file 2.png :results value graphics
library(lattice)
print(xyplot(1:10 ~ 1:10))
#+end_src
* does produce a file, by using :results output
#+begin_src R :file 3.png :results output graphics
library(lattice)
xyplot(1:10 ~ 1:10)
#+end_src
* does produce a file, by evaluating in :session
#+begin_src R :file 4.png :session :results graphics
library(lattice) …