title: How to represent those types of values in a tensor?
body: <p>I have a dataset like this:</p>
  <pre><code>(0, 1), UpDownUpUp            
  (2, 3), UpUpUpDownDownDown   
  (0, 2), DownUp               
  (0, Undefined), DownUp   
  </code></pre>
  <p>How to represent this type of data in a PyTorch tensor? So I can then train a neural network with it?</p>