title: Numpy index without using slice
body: <p>Suppose I have an array A whose shape is (4,3,2).
  Is there anyway to represent something like A[:,1,1] or A[3,:,0] without using slice syntax?</p>
  
  <p>Lets say I have a possibility table p(A,B,C) with a shape (4,3,2). Given two states of any two variables, I need to know the other variable's possibility table. But I don't know which two variables' states I will know in advance. So I can't use slicing syntax.</p>
  
  <pre><code>pABC=np.array([
      [[ 0.9 ,  0.3 ],
      [ 0.8 ,  0.4 ],
      [ 0.1 ,  0.01]],
     [[ 0.08,  0.05],
      [ 0.17,  0.05],
      [ 0.01,  0.01]],
     [[ 0.01,  0.05],
      [ 0.01,  0.15],
      [ 0.87,  0.97]],
     [[ 0.01,  0.6 ],
      [ 0.02,  0.4 ],
      [ 0.02,  0.01]]])
  </code></pre>
  
  <p>Sometimes I need to index [:,0,1], sometimes I need to index [2,:,0]. I need to write a function for this indexing operation. So I can't use slicing in my function because I don't know which axis I need to slice.</p>
  
  <p>Thanks!</p>