title: Check if R is installed from python
body: <p>I have a <code>python</code> code that calls many functions and one of those functions needs the <a href="http://cran.r-project.org/" rel="nofollow"><code>R</code> software</a> installed to be able to run properly.</p>
  
  <p>How can I check from within <code>python</code> if <code>R</code> is installed in the system so as to avoid calling that function if it is not?</p>
  
  <p>BTW I'm running a Linux distro (elementary OS, based on Ubuntu 12.04)</p>