Python Pandas - Display unique values present in each column

To display unique values in each column, use the unique() method and set the column within it. At first, import the required library ?

import pandas as pd

Create a DataFrame with two columns and duplicate records ?

import pandas as pd

dataFrame = pd.DataFrame(
    {
        "Student": ['Jack', 'Robin', 'Ted', 'Robin', 'Scarlett', 'Kat', 'Ted'],
        "Result": ['Pass', 'Fail', 'Pass', 'Fail', 'Pass', 'Pass', 'Pass']
    }
)

print("DataFrame ...")
print(dataFrame)

DataFrame ...
   Student    Result
0     Jack      Pass
1    Robin      Fail
2      Ted      Pass
3    Robin      Fail
4 Scarlett      Pass
5      Kat      Pass
6      Ted      Pass

Using pd.unique() Method

Find unique values by setting each column in the unique() method ?

import pandas as pd

dataFrame = pd.DataFrame(
    {
        "Student": ['Jack', 'Robin', 'Ted', 'Robin', 'Scarlett', 'Kat', 'Ted'],
        "Result": ['Pass', 'Fail', 'Pass', 'Fail', 'Pass', 'Pass', 'Pass']
    }
)

# Finding unique values
resStudent = pd.unique(dataFrame.Student)
resResult = pd.unique(dataFrame.Result)

print("Unique values in Student Column:", resStudent)
print("Unique values in Result Column:", resResult)

Unique values in Student Column: ['Jack' 'Robin' 'Ted' 'Scarlett' 'Kat']
Unique values in Result Column: ['Pass' 'Fail']

Alternative Method Using Column unique()

You can also call unique() directly on the DataFrame column ?

import pandas as pd

dataFrame = pd.DataFrame(
    {
        "Student": ['Jack', 'Robin', 'Ted', 'Robin', 'Scarlett', 'Kat', 'Ted'],
        "Result": ['Pass', 'Fail', 'Pass', 'Fail', 'Pass', 'Pass', 'Pass']
    }
)

# Alternative approach using column.unique()
print("Unique Students:", dataFrame['Student'].unique())
print("Unique Results:", dataFrame['Result'].unique())

Unique Students: ['Jack' 'Robin' 'Ted' 'Scarlett' 'Kat']
Unique Results: ['Pass' 'Fail']

Getting Unique Values for All Columns

To get unique values for all columns at once, you can use a loop ?

import pandas as pd

dataFrame = pd.DataFrame(
    {
        "Student": ['Jack', 'Robin', 'Ted', 'Robin', 'Scarlett', 'Kat', 'Ted'],
        "Result": ['Pass', 'Fail', 'Pass', 'Fail', 'Pass', 'Pass', 'Pass']
    }
)

# Get unique values for all columns
for column in dataFrame.columns:
    print(f"Unique values in {column}:", dataFrame[column].unique())

Unique values in Student: ['Jack' 'Robin' 'Ted' 'Scarlett' 'Kat']
Unique values in Result: ['Pass' 'Fail']

Conclusion

Use pd.unique() or column.unique() to find unique values in DataFrame columns. Both methods return an array of unique values, preserving the order of first occurrence.