title: How do I convert a 2D list into a set?
body: <p>So far I've only found this:</p>
  
  <pre><code>myList = [[32, 12, 52, 63], [32, 64, 67, 52], [64,64,17,34], [17, 76, 98]]
  
  mySet = set(i for j in mylist for i in j)
  </code></pre>
  
  <p>As far as I can tell, this is working, but I have no idea why it works.
  Could somebody please walk me step by step how the "mySet = set(i for j in mylist for i in j)" bit actually works.</p>