List of count of unique values in all pandas columns code example
Example 1: count unique pandas
df['column'].nunique()
Example 2: get count of unique values in column pandas
df = df.groupby('domain')['ID'].nunique()
print (df)
domain
'facebook.com' 1
'google.com' 1
'twitter.com' 2
'vk.com' 3
Name: ID, dtype: int64