title: Pandas GroupBy- Remove groups with less than 2 items
body: <p>I've got a Pandas DataFrame of ID's which I've grouped by 5 columns.</p>
  <p>Looking to obtain an output of groups containing only 2 or more IDs. Or at the very least, sort by number of IDs (descending).</p>
  <pre><code>for key, item in grouped:
  
      print(key)
      print(item['ID'])
      print()
  </code></pre>
  <p>Got the above to achieve a long list of keys and their IDs, wondering if I need to incorporate some sort of size() command in there to achieve the desired output?</p>
  <p>Looking for an output like this:</p>
  <pre><code>('Met', 59.0, 0.0, 0.0, 196.0, 66.0)
  702     510000261554
  1184    510000247456
  Name: ID, dtype: int64
  </code></pre>
  <p>Quite new to coding so would really appreciate any help!</p>