title: Python: Converting nanoseconds into DateTime64 format
body: <p>I have a column of <code>timestamps</code> in seconds (since midnight) with nanosecond precisions like <code>34200.934549345, 34205.735545344</code>, and so on in a DataFrame <code>df</code>. </p>
  
  <p>These <code>timestamps</code> come from the same day <code>2011-01-10</code>. </p>
  
  <p>How can I convert these seconds with nanosecond precision in the <code>DateTime64</code> format of <code>numpy</code>?</p>
  
  <p>I would like to have these entries in my <code>df</code> </p>
  
  <pre><code>2011-01-10 9:30:00.934549345
  2011-01-10 9:30:05.735545344
  </code></pre>
  
  <p>I need to do the exact operation like in this <a href="https://stackoverflow.com/questions/15930885/converting-irregularly-time-stamped-measurements-into-equally-spaced-time-weigh">example</a> under SOLUTION of the asked question. </p>
  
  <p>Is it possible?</p>