title: How can I negate the %in% operator (or return the complement of two sets)?
body: <p>I have two lists or similar, and I want to get the items in <code>big_list</code> that are <em>not</em> in <code>little_list</code>.</p>
  
  <pre><code>big_list  &lt;- c(1,2,3,4,5)
  little_list  &lt;- c(2,4)
  big_list[big_list %in% little_list] # this gives me the interection
  </code></pre>
  
  <p>But I want the complement (items in big_list that aren't in little_list, i.e. <code>big_list\little_list</code>).</p>
  
  <p>This doesn't work</p>
  
  <pre><code>big_list[big_list ! %in% little_list]
  </code></pre>
  
  <p>Neither does this</p>
  
  <pre><code>big_list[big_list %in% ! little_list]
  </code></pre>
  
  <p>I am assuming there is an answer I should have worked out by myself?!</p>