Pandas dataframe.nunique() Method Last Updated : 29 Mar, 2023 Comments Improve Suggest changes Like Article Like Report Python is a great language for doing data analysis, primarily because of the fantastic ecosystem of data-centric Python packages. Pandas is one of those packages and makes importing and analyzing data much easier. Pandas DataFrame.nunique Syntax Pandas dataframe.nunique() function returns a Series with a number of distinct observations over the requested axis. If we set the value of the axis to 0, then it finds the total number of unique observations over the index axis. If we set the value of the axis to 1, then it finds the total number of unique observations over the column axis. It also provides the feature to exclude the NaN values from the count of unique numbers. Syntax: DataFrame.nunique(axis=0, dropna=True) Parameters: axis : {0 or ‘index’, 1 or ‘columns’}, default 0dropna : Don’t include NaN in the counts. Returns : nunique : Series Pandas DataFrame nunique() Method Example 1: Use nunique() function to find the number of unique values over the column axis. Python3 # importing pandas as pd import pandas as pd # Creating the first dataframe df = pd.DataFrame({"A":[14, 4, 5, 4, 1], "B":[5, 2, 54, 3, 2], "C":[20, 20, 7, 3, 8], "D":[14, 3, 6, 2, 6]}) # Print the dataframe df Output: Let's use the dataframe.nunique() function to find the unique values across the column axis. Python3 # find unique values df.nunique(axis=1) Output: As we can see in the output, the function prints the total no. of unique values in each row. Example 2: Use nunique() function to find the number of unique values over the index axis in a Dataframe. The Dataframe contains NaN values. Python3 # importing pandas as pd import pandas as pd # Creating the first dataframe df = pd.DataFrame({"A": ["Sandy", "alex", "brook", "kelly", np.nan], "B": [np.nan, "olivia", "olivia", "", "amanda"], "C": [20 + 5j, 20 + 5j, 7, None, 8], "D": [14.8, 3, None, 6, 6]}) # apply the nunique() function df.nunique(axis=0, dropna=True) Output: The function is treating the empty string as a unique value in column 2. Comment More infoAdvertise with us Next Article Pandas dataframe.nunique() Method S Shubham__Ranjan Follow Improve Article Tags : Technical Scripter Python Python-pandas Python pandas-dataFrame Pandas-DataFrame-Methods +1 More Practice Tags : python Similar Reads Pandas Functions in Python: A Toolkit for Data Analysis Pandas is one of the most used libraries in Python for data science or data analysis. It can read data from CSV or Excel files, manipulate the data, and generate insights from it. Pandas can also be used to clean data, filter data, and visualize data. 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