title: Python equivalent R code - numeric seconds from epoch to POSIXlt
body: <p>I have number of seconds elapsed since an epoch and can convert it to localtime in python, like so </p>
  
  <pre><code>time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(1378182603));
  ## yields '2013-09-03 10:00:03'
  </code></pre>
  
  <p>How can I achieve the same in R?</p>