title: How to join two sets in one line without using "|"
body: <p>Assume that <code>S</code> and <code>T</code> are assigned sets. Without using the join operator <code>|</code>, how can I find the union of the two sets? This, for example, finds the intersection: </p>
  
  <pre><code>S = {1, 2, 3, 4}
  T = {3, 4, 5, 6}
  S_intersect_T = { i for i in S if i in T }
  </code></pre>
  
  <p>So how can I find the union of two sets in one line without using <code>|</code>?</p>