title: Python, Numpy: How to select numpy array with given mask
body: <p>For example, given a (10000, 250) sized numpy matrix A</p>
  
  <pre><code>&gt;&gt;&gt;A.shape
  (10000, 250)
  </code></pre>
  
  <p>and a numpy mask array <code>m</code></p>
  
  <pre><code>&gt;&gt;&gt;m = np.arange(0, A.shape[0], 3)
  &gt;&gt;&gt;m
  ([0, 3, 6, 9, ....., 9997])
  </code></pre>
  
  <p>This will select wanted column of <code>A</code></p>
  
  <pre><code>&gt;&gt;&gt;A[m]
  &gt;&gt;&gt;A[m].shape
  (3333, 250)
  </code></pre>
  
  <p>But my question is. how to select the rest of the <code>A</code>? <code>A[([1, 2, 4, 5, 7, 8, ...., 9998, 9999, 10000])]</code></p>