Get unique values from a column in Pandas DataFrame

Let’s discuss how to get unique values from a column in Pandas DataFrame.

Create a simple dataframe with dictionary of lists, say columns name are A, B, C, D, E with duplicate elements.

Now, let’s get the unique values of a column in this dataframe.

Example #1: Get the unique values of ‘B’ column

# Import pandas package  

import pandas as pd 

# create a dictionary with five fields each 

data = { 

    'A':['A1', 'A2', 'A3', 'A4', 'A5'],  

    'B':['B1', 'B2', 'B3', 'B4', 'B4'],  

    'C':['C1', 'C2', 'C3', 'C3', 'C3'],  

    'D':['D1', 'D2', 'D2', 'D2', 'D2'],  

    'E':['E1', 'E1', 'E1', 'E1', 'E1'] } 

# Convert the dictionary into DataFrame  

df = pd.DataFrame(data) 

# Get the unique values of 'B' column 
df.B.unique()

Output:

Example #2: Get the unique values of ‘E’ column

# Import pandas package  

import pandas as pd 

# create a dictionary with five fields each 

data = { 

    'A':['A1', 'A2', 'A3', 'A4', 'A5'],  

    'B':['B1', 'B2', 'B3', 'B4', 'B4'],  

    'C':['C1', 'C2', 'C3', 'C3', 'C3'],  

    'D':['D1', 'D2', 'D2', 'D2', 'D2'],  

    'E':['E1', 'E1', 'E1', 'E1', 'E1'] } 

# Convert the dictionary into DataFrame  

df = pd.DataFrame(data) 

# Get the unique values of 'E' column 
df.E.unique()

Output:

Example #3: Get number of unique values in a column

# Import pandas package  

import pandas as pd 

# create a dictionary with five fields each 

data = { 

    'A':['A1', 'A2', 'A3', 'A4', 'A5'],  

    'B':['B1', 'B2', 'B3', 'B4', 'B4'],  

    'C':['C1', 'C2', 'C3', 'C3', 'C3'],  

    'D':['D1', 'D2', 'D2', 'D2', 'D2'],  

    'E':['E1', 'E1', 'E1', 'E1', 'E1'] } 

# Convert the dictionary into DataFrame  

df = pd.DataFrame(data) 

# Get number of unique values in column 'C' 

df.C.nunique(dropna = True)