title: How to find duplicate names using pandas?
body: <p>I have a <code>pandas.DataFrame</code> with a column called <code>name</code> containing strings.
  I would like to get a list of the names which occur more than once in the column. How do I do that?</p>
  
  <p>I tried:</p>
  
  <pre><code>funcs_groups = funcs.groupby(funcs.name)
  funcs_groups[(funcs_groups.count().name&gt;1)]
  </code></pre>
  
  <p>But it doesn't filter out the singleton names.</p>