title: Reading .dat file date string
body: <p>In Python:</p>
  
  <p>Got a .dat file one column is a datestr 'yyyy-mm-dd'. Column years range from 2000, to 2010 I only want to use 2005.</p>
  
  <p>How can I successfully read using np.loadtxt, keeping in the same format.</p>
  
  <p>I am then going to use:</p>
  
  <pre><code>time_string = yyyy-mm-dd
  doy = int (time.strftime ("%j", time.strptime ( time_string, "%Y, %m, %d")))
  </code></pre>
  
  <p>to convert yyyy-mm-dd to day of year (1-365)</p>