# importing libraries 

import numpy as np 

import pandas as pd 

from pandas.api.types import CategoricalDtype 

labels, uniques = pd.factorize(['b', 'd', 'd', 'c', 'a', 'c', 'a', 'b']) 

print(labels)

# [0 1 1 2 3 2 3 0]

​

print(uniques)

# ['b' 'd' 'c' 'a']