How to set the R_HOME environment variable to the R home directory?

Question

I am trying to import rpy2 into python and I am getting this error:

RuntimeError: The R home directory could not be determined.
Try to install R 

        

Answer 1

It is the other way around -- the R in your PATH should know its home:

edd@don:~$ R RHOME
/usr/lib/R
edd@don:~$ 

This echos the last line recommendation -- have your R in the PATH.

On another machine with both R and R-devel, I choose to address the latter under a different name. Still, each knows its HOME:

edd@max:~$ /usr/local/lib/R-devel/bin/R RHOME
/usr/local/lib/R-devel/lib/R
edd@max:~$ R RHOME
/usr/lib/R
edd@max:~$ 

Answer 2

Setting R_HOME this way worked for me

import os
os.environ['R_HOME'] = '/path/to/R'