title: Filtering numpy array of numpy arrays
body: <p>I've got a np array of arrays and I want to remove all elements that match a condition. I want to avoid <strong>for</strong> loops to try to make it faster.</p>
  
  <p>The np array is of shape [N,2]. I want to remove all sub-arrays where the first element is equal to zero.</p>
  
  <pre><code>[[1,2],
   [0,5], # &lt;--- Remove
   [5,1],
   [0,3], # &lt;--- Remove
   [1,1],
   [0,0], # &lt;--- Remove
   [5,0],
   .....
   [5,5]] 
  </code></pre>
  
  <p>I hope there is a solution with just one line of code. I just can't figure this line out. I hope somebody can help me.</p>
  
  <p>Thank you.</p>