pandas groupby count unique values in column 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 groupby count unique rows

ID, domain
123, 'vk.com'
123, 'vk.com'
123, 'twitter.com'
456, 'vk.com'
456, 'facebook.com'
456, 'vk.com'
456, 'google.com'
789, 'twitter.com'
789, 'vk.com'