title: How to count the number of ocurrences of events in column and output in new colum sorted by user with pandas
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  <p>I'm trying to count the number of occurrences each number is found in column &quot;event_type_id&quot; and group by user and save it to a new column using pandas.
  Ex: on Column A, User 1 completed the actions that are labeled in column C. I want to count how many times User A did event &quot;0&quot; and add that sum to the new column called &quot;Post&quot;
  Can anyone help?</p>