Quick method to find cross index between two numpy arrays
<p>Lets say that I have a 2 dimensional array such as:</p>

<pre><code>x=array([[1,2,3],[4,5,6],[7,8,9]])
</code></pre>

<p>And another holding the same values but in a different order and size perhaps, such as:</p>

<pre><code>y=array([[4,5,6],[1,2,3],[7,8,9],[1,2,3]])
</code></pre>

<p>I would like a quick method using no dictionaries or lists 
(already done that) to find the index locations of y with respect to x. 
So the output would be:</p>

<pre><code>z=array([1,0,2,0])
</code></pre>

<p>Thanks!</p>