title: Invert binary numpy array
body: <p>is there a kind of "logical no" for numpy arrays (of numbers of course).</p>
  
  <p>For example, consider this array:
  <code>x = [1,0,1,0,0,1]</code></p>
  
  <p>i am looking for an easy way to compute its "inverse"
  <code>y = [0,1,0,1,1,0]</code></p>