title: Pandas loc find user that has applied to 5 or more things
body: <p>I want to know which users have a FullCategory of length greater than 5.</p>
  
  <p>I currently have a data frame called users_df that looks like this</p>
  
  <pre><code>UserId  FullCategory
  1       [1,2,3,4,5]
  2       [1,2,,5]
  3.      [1,4,5]
  </code></pre>
  
  <p>I am trying to do this. </p>
  
  <pre><code>users_df.loc[len(users_df.FullCategory) &gt; 5, :]
  </code></pre>
  
  <p>But it doesn't seem to work</p>