title: Python: intersection indices numpy array
body: <p>How can I get the indices of intersection points between two numpy arrays? I can get intersecting values with <code>intersect1d</code>:</p>
  
  <pre><code>import numpy as np
  
  a = np.array(xrange(11))
  b = np.array([2, 7, 10])
  inter = np.intersect1d(a, b)
  # inter == array([ 2,  7, 10])
  </code></pre>
  
  <p>But how can I get the indices into <code>a</code> of the values in <code>inter</code>?</p>