title: How to convert dd/mm/yy to yyyy-mm-dd in R
body: <p>I have a vector with dates values in this format dd/mm/yy e.g.(27/06/16).
  I want to convert this in this format yyyy-mm-dd e.g.(2016-06-27) for logical comparison. I am using this expression:</p>
  
  <pre><code>as.Date(as.character("27/06/16"), format = "%d")
  </code></pre>
  
  <p>and output comes out as:</p>
  
  <pre><code>"2016-07-27"
  </code></pre>
  
  <p>How can I convert this into required format.</p>