title: Python Speedup np.unique
body: <p>I am looking to speed up the following piece of code:</p>
  
  <pre><code>NNlist=[np.unique(i) for i in NNlist] 
  </code></pre>
  
  <p>where NNlist is a list of np.arrays with duplicated entries.</p>
  
  <p>Thanks :)</p>