title: Get indices of elements that are greater than a threshold in 2D numpy array
body: <p>I have a 2D numpy array:</p>
  
  <pre><code>x = [[  1.92043482e-04   0.00000000e+00   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00   2.41005634e-03   0.00000000e+00
      7.19330120e-04   0.00000000e+00   0.00000000e+00   1.42886875e-04
      0.00000000e+00   0.00000000e+00   0.00000000e+00   0.00000000e+00
      0.00000000e+00   9.79279411e-05   7.88888657e-04   0.00000000e+00
      0.00000000e+00   1.40425916e-01   0.00000000e+00   1.13955893e-02
      7.36868947e-03   3.67091988e-04   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00   1.72037105e-03   1.72377961e-03
      0.00000000e+00   0.00000000e+00   1.19532061e-01   0.00000000e+00
      0.00000000e+00   0.00000000e+00   0.00000000e+00   3.37249481e-04
      0.00000000e+00   0.00000000e+00   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00   1.75111492e-03   0.00000000e+00
      0.00000000e+00   1.12639313e-02]
   [  0.00000000e+00   0.00000000e+00   1.10271735e-04   5.98736562e-04
      6.77961628e-04   7.49569659e-04   0.00000000e+00   0.00000000e+00
      2.91697850e-03   0.00000000e+00   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00   3.30257021e-04   2.46629275e-04
      0.00000000e+00   1.87586441e-02   6.49103144e-04   0.00000000e+00
      1.19046355e-04   0.00000000e+00   0.00000000e+00   2.69499898e-03
      1.48525386e-02   0.00000000e+00   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00   0.00000000e+00   1.18803119e-03
      3.93100829e-04   0.00000000e+00   3.76245304e-04   2.79537738e-02
      0.00000000e+00   1.20738457e-03   9.74669064e-06   7.18680093e-04
      1.61546793e-02   3.49360861e-04   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00   0.00000000e+00   0.00000000e+00
      0.00000000e+00   0.00000000e+00]]
  </code></pre>
  
  <p>How do I get indices of the elements that are greater than <code>0.01</code>?</p>
  
  <p>Right now, I'm doing <code>t = np.argmax(x, axis=1)</code> to get the index of the maximum value from each and the result of it is: <code>[21 35]</code>. How do I achieve the above?</p>