title: drop row if there are more than 10 similar rows (pandas)
body: <p>I have encountered an interesting problem regarding sorting and filtering dataframes. What I am trying to do is to merge two data frames with matching time data. However, while trying to do this I stumbled upon a problem. When taking a look at the second data frame I see that the data is recorded with an irregular frequency. Visualized below:</p>
  <pre><code>11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.725775179245232
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.726649020300092
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.72729159079124
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.727677715607114
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.728880087146763
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.729360473905706
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.730057032586954
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.73087151228958
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.731687795062698
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.732025075281149
  11-Nov-2020 03:24:13,65.2483683333333,21.6083716666667,53,2,0.732264359809922
  11-Nov-2020 03:24:14,65.2483683333333,21.6083716666667,53,2,0.735130987737598
  11-Nov-2020 03:24:14,65.2483683333333,21.6083716666667,53,2,0.736691273093919
  11-Nov-2020 03:24:14,65.2483683333333,21.6083716666667,53,2,0.740142318585631
  11-Nov-2020 03:24:14,65.2483683333333,21.6083716666667,53,2,0.738218394663463
  11-Nov-2020 03:24:14,65.248355,21.6086866666667,53.2,2,0.735181734805166
  11-Nov-2020 03:24:14,65.248355,21.6086866666667,53.2,2,0.734764836369492
  11-Nov-2020 03:24:14,65.248355,21.6086866666667,53.2,2,0.735047479962169
  11-Nov-2020 03:24:14,65.248355,21.6086866666667,53.2,2,0.7354234562092
  11-Nov-2020 03:24:14,65.248355,21.6086866666667,53.2,2,0.73582921509618
  11-Nov-2020 03:24:14,65.248355,21.6086866666667,53.2,2,0.734441003913533
  -&gt; 11-Nov-2020 03:24:14,65.24834,21.6090016666667,53.4,2,0.734780511599276
  </code></pre>
  <p>On the last row, you can see it has the same time data as the one above it. However, there are 11 rows with the time <code>03:24:14</code> (as you can see above).</p>
  <p>Because of this, I am not able to merge with my other dataframe that has a constant frequency of 10hz. That's why I would like to remove the 11th row (in a time period that recorded 11 points with the same time data).</p>
  <p>Is this possible? Thank you in advance!</p>