title: how to create similarity matrix in numpy python?
body: <p>I have data in a file in following form:</p>
  
  <pre><code>user_id, item_id, rating
  1, abc,5
  1, abcd,3
  2, abc, 3
  2, fgh, 5
  </code></pre>
  
  <p>So, the matrix I want to form for above data is following:</p>
  
  <pre><code>#   itemd_ids
  # abc  abcd  fgh
  [[5,    3,    0]  # user_id 1
   [3,    0,    5]] # user_id 2
  </code></pre>
  
  <p>where missing data is replaced by 0. </p>
  
  <p>But from this I want to create both user to user similarity matrix and item to item similarity matrix?</p>
  
  <p>How do I do that?</p>