title: How to select rows in Pandas dataframe where value appears more than once
body: <p>Let's say I have the Pandas dataframe with columns of different measurement attributes and corresponding measurement values.</p>
  
  <pre><code>ID     Parameter     Value
  0      'A'           4.3
  1      'B'           3.1
  2      'C'           8.9
  3      'A'           2.1
  4      'A'           3.9
  .      .             .
  .      .             .
  .      .             .
  100    'B'           3.8
  </code></pre>
  
  <p>How can I filter this dataframe to only have measurements that appear more than X number of times? For example, for this dataframe I want to get all rows with more than 5 measurements (lets say only parameters 'A' and 'B' appear more than 5 times) to get a dataframe like below. </p>
  
  <pre><code>ID     Parameter     Value
  0      'A'           4.3
  1      'B'           3.1
  3      'A'           2.1
  .      .             .
  .      .             .
  .      .             .
  100    'B'           3.8
  </code></pre>