title: Tuple as index of multidimensional array
body: <p>I found a very similar question to mine, but not exactly the same.
  This one: <a href="https://stackoverflow.com/questions/2444923/unpacking-tuples-arrays-lists-as-indices-for-numpy-arrays">here</a>
  However in ntimes's case the size of the array matches the number of the dimensions the tuple is point at.
  In my case I have a 4-dimensional array and a 2-dimensional tuple, just like this:</p>
  
  <pre><code>from numpy.random import rand
  big_array=rand(3,3,4,5)
  tup=(2,2)
  </code></pre>
  
  <p>I want to use the tuple as an index to the first two dimensions, and manually index the last two. Something like:</p>
  
  <pre><code>big_array[tup,3,2]
  </code></pre>
  
  <p>However, I obtain a repetition of the first dimension with index=2, along the fourth dimension( since it technically hasn't been indexed). That is because this indexing is interpreting a double indexing to the first dimension instead of one value for each dimension, </p>
  
  <pre><code>eg. 
  | dim 0:(index 2 AND index 2) , dim 1:(index 3), dim 2:(index 2), dim 3:(no index)|
  instead of 
  |dim 0(index 2), dim 1(index 2), dim 2:(index 3), dim 3:(index 2)|.
  </code></pre>
  
  <p>How can I 'unpack' this tuple then? Any ideas?
  thanks!</p>