Pandas cannot compute isin with a duplicate axis

Question

My dataframe is something like this:

             userid           codeassigned         timestamp
15           553938              M1           1499371200000         


        

Answer 1

You need merge for inner join with filtered subset:

subset_df = df.loc[~mask, ['userid', 'timestamp']]

df = subset_df.merge(df)

Or:

df = subset_df[['userid', 'timestamp']].merge(df)