title: R: Time stamps, Unix time and correct usage of 'strptime'
body: <p>I have a column named <code>timings</code> of class <code>factor</code> with time stamps in the following format:</p>
  
  <pre><code>1/11/07 15:15
  </code></pre>
  
  <p>I applied strptime on <code>timings</code> to  generate <code>tStamp</code> as follows:</p>
  
  <pre><code>tStamp=strptime(timings,format="%m/%d/%Y %H:%M")
  </code></pre>
  
  <p>i)
  The corresponding entry in tStamp looks like <code>0007-01-11 15:15:00</code> now. Why has it made <code>2007</code> or <code>07</code> into <code>0007</code>? What is a correct way to generate <code>tStamp</code>?</p>
  
  <p>ii) 
  After generating <code>tStamp</code> correctly, how do we convert it to the Unix time Seconds. (Seconds since...1970) format?</p>