title: Access line by line to a numpy structured array
body: <p>I am trying to access to a structured array line by line by iterating on the values of one field of it but even if the value iterate well, the slice of the array doesn't change. Here is my SWE :</p>
  
  <pre><code>import numpy as np
  dt=np.dtype([('name',np.unicode,80),('x',np.float),('y',np.float)])
  a=np.array( [('a',0.,0.),('b',0.,0.),('c',0.,0.) ],dtype=dt)
  for n in a['name']:
    print n,a['name'==n]
  </code></pre>
  
  <p>gives me :</p>
  
  <pre><code>a (u'a', 0.0, 0.0)
  b (u'a', 0.0, 0.0)
  c (u'a', 0.0, 0.0)
  </code></pre>
  
  <p>At each iteration, I always have the same slice of the array... strange ?</p>