title: How can I keep only somes values in array, list?
body: <p>I have this array such as :</p>
  
  <p><code>a = numpy.array([10,15,20,36,58])</code>
  <code>b = [10,15,20,36,58]</code></p>
  
  <p>And I would like to keep for a and b the values which are higher than 20 ie to get the following array/list :</p>
  
  <p><code>c = [20,36,58]</code>
  <code>d = numpy.array([20,36,58])</code></p>
  
  <p>Do you know how can I do this ?</p>