title: The R equivalent of Python `from x import y as z`
body: <p>In python I can load a specific function or functionality with:</p>
  
  <p><code>from x import y as z</code></p>
  
  <p>How can I replicate this in R?</p>
  
  <p>For instance, I want to load <em>just</em> the <code>count</code> function from <code>plyr</code>, 
  instead of loading the entire package with <code>library(plyr)</code></p>