title: numpy where returns an array. I need just index
body: <p>I have a numpy array: <code>k = np.array([100,20,25,10,1,2])</code> and I'm trying to use a np where as <code>index=np.where(k&lt;10)</code> which gives me 
  <code>index (array([4, 5]),)</code>. I'm insterested in something to give me just the index so here I'd like to have <code>index[0]=4</code> not <code>index[0]=[4 5]</code></p>
  
  <p>I couldn't find anything here on the numpy docs.</p>