pandas group by count distinct code example

Example 1: 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()

Example 2: pandas count the number of unique values in a column

df['hID'].nunique()
5

Example 3: 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