Python | Pandas.factorize() Last Updated : 27 Sep, 2018 Improve Improve Like Article Like Save Share Report pandas.factorize() method helps to get the numeric representation of an array by identifying distinct values. This method is available as both pandas.factorize() and Series.factorize(). Parameters: values : 1D sequence. sort : [bool, Default is False] Sort uniques and shuffle labels. na_sentinel : [ int, default -1] Missing Values to mark ‘not found’. Return: Numeric representation of array Code: Explaining the working of factorize() method # 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("Numeric Representation : \n", labels) print("Unique Values : \n", uniques) # sorting the numerics label1, unique1 = pd.factorize(['b', 'd', 'd', 'c', 'a', 'c', 'a', 'b'], sort = True) print("\n\nNumeric Representation : \n", label1) print("Unique Values : \n", unique1) # Missing values indicated label2, unique2 = pd.factorize(['b', None, 'd', 'c', None, 'a', ], na_sentinel = -101) print("\n\nNumeric Representation : \n", label2) print("Unique Values : \n", unique2) # When factorizing pandas object; unique will differ a = pd.Categorical(['a', 'a', 'c'], categories =['a', 'b', 'c']) label3, unique3 = pd.factorize(a) print("\n\nNumeric Representation : \n", label3) print("Unique Values : \n", unique3) Like Article Suggest improvement Next Python | Pandas Index.factorize() Share your thoughts in the comments Add Your Comment Please Login to comment... Similar Reads Python | Pandas Index.factorize() Python | Pandas TimedeltaIndex.factorize Python | Pandas Series.factorize() Python | pandas.to_markdown() in Pandas Python Pandas - pandas.api.types.is_file_like() Function Add a Pandas series to another Pandas series Pandas DataFrame hist() Method | Create Histogram in Pandas Pandas DataFrame iterrows() Method | Pandas Method Pandas DataFrame interpolate() Method | Pandas Method Pandas DataFrame duplicated() Method | Pandas Method Like M Mohit Gupta_OMG :) Follow Article Tags : Python pandas-series Python pandas-series-methods Python-pandas Python Practice Tags : python