Answers for "pandas count unique groupby"

pandas groupby column count distinct values

# Pandas group by a column looking at the count unique/count distinct values of another column

df.groupby('param')['group'].nunique()

pandas groupby count unique rows

df = df.groupby(by='domain', as_index=False).agg({'ID': pd.Series.nunique})
print(df)
    domain  ID
0       fb   1
1      ggl   1
2  twitter   2
3       vk   3