title: How to make an adjacency matrix out of a list?
body: <p>I have a list like:</p>
  
  <pre><code>[['10', '20', 2], ['10', '21', 2], ['10', '1', 2], ['10', '0', 3], ['10', '3', 2],
   ['10', '2', 2], ['10', '5', 3], ['10', '4', 3], ['10', '7', 2], ['10', '6', 2],
   ['10', '9', 2], ['10', '8', 2], ['10', '11', 2], ['10', '10', 2], ['10', '13', 2],
   ['10', '12', 2], ['10', '15', 2], ['10', '14', 2], ['10', '17', 0], ['10', '16', 3],
   ['10', '19', 2], ['10', '18', 2], ['1', '20', 3], ['1', '21', 3], ['1', '1', 3],
   ['1', '0', 0], ['1', '3', 3], ['1', '2', 3], ['1', '5', 4], ['1', '4', 4],
   ['1', '7', 3], ['1', '6', 3], ['1', '9', 3], ['1', '8', 3], ['1', '11', 3],
   ['1', '10', 3], ['1', '13', 3], ['1', '12', 3], ['1', '15', 3]]
  </code></pre>
  
  <p>(it's a lot bigger than this) which the first and second item are actually node names and the third one is the edge weight between them (I didn't make a graph though, it's a list). </p>
  
  <p>I'd like to make an adjacency matrix out of this list. </p>