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)

Output: