There is a Pandas dataframe: userId movieId rating timestamp 0 1 31 2.5 1260759144 1 1 1029 3.0 1260759179 2 1 1061 3.0 1260759182 3 1 1129 2.0 1260759185 4 1 1172 4.0 1260759205 leave in this dataframe only users who have rated 100 or more in the rating column in the rating column put the average rating which the user gave

df.groupby('userId').filter(lambda x: len(x) >= 100)
df.groupby('userId').mean()