title: Why does numpy.datetime64 give an error with an array of years?
body: <p>I am working with some data that has the date in the format 2017.08333. In the process of converting this to datetime objects I got an error when trying to convert the integer years to datetime.    </p>
  
  <pre><code>np.datetime64(['2017','2018'])
  </code></pre>
  
  <p>The above fails with the error:<code>Could not convert object to NumPy datetime</code></p>
  
  <p>I was under the impression numpy functions were vectorized. Can someone explain why this doesn't work and how I can solve this? I have 3,000 dates to convert so something that doesn't involve a loop is ideal.</p>