title: Unable to add an element to a Numpy Array
body: <p>I'm trying to add an element to the Numpy array. I'm doing something like this (putting in snippets of code, so please let me know if i'm missing some crucial info - and i'll add to it). I'd like someone to help explain what i'm doing wrong in the np.append function.</p>
  
  <p>====================================</p>
  
  <pre><code>#Data type declaration for each element of array.
  dt = [
      ('device', 'int64'),
      ('battery', 'u2'),
      ('version', 'f4'),
      ('ChargeStatus', 'u2'),
      ('temperature', 'u2'),
      ('time', 'datetime64'),
      ]
  
  #dataArr is the final array and data is the individual element. 
  
  dataArr = np.zeros(0, dtype=dt)
  data = np.empty(1, dtype=dt)
  
  &lt;snip - code that reads a file, parses and writes into "data"&gt; 
  
  #The following line of code does NOT write any data into dataArr
  np.append (dataArr, data)
  
  #However, if i change the above line as below, dataArr gets the populated array i'm looking for. 
  
  dataArr = np.append (dataArr, data)
  </code></pre>