GroupBy and Apply different functions using a Dictionary in Pandas

Last update on April 11 2025 12:50:53 (UTC/GMT +8 hours)

12. GroupBy and Applying Different Functions Using a Dictionary

Write a Pandas program that uses dictionaries to apply different functions to different columns in GroupBy.

Sample Solution:

Python Code :

import pandas as pd

# Sample DataFrame
data = {'Category': ['A', 'A', 'B', 'B', 'C', 'C'],
        'Value1': [1, 2, 3, 4, 5, 6],
        'Value2': [10, 20, 30, 40, 50, 60]}

df = pd.DataFrame(data)
print("Sample DataFrame:")
print(df)

# Group by 'Category' and apply different functions using a dictionary
print("\nGroup by 'Category' and apply different functions using a dictionary:")
grouped = df.groupby('Category').agg({'Value1': 'sum', 'Value2': 'mean'})

print(grouped)

Output:

Sample DataFrame:
  Category  Value1  Value2
0        A       1      10
1        A       2      20
2        B       3      30
3        B       4      40
4        C       5      50
5        C       6      60

Group by 'Category' and apply different functions using a dictionary:
          Value1  Value2
Category                
A              3    15.0
B              7    35.0
C             11    55.0

Explanation:

Import pandas.
Create a sample DataFrame.
Group by 'Category'.
Apply sum aggregation on 'Value1' and mean aggregation on 'Value2' using a dictionary.
Print the result.

For more Practice: Solve these Related Problems:

Write a Pandas program to group data and apply a dictionary of functions to different columns, then display the aggregated results.
Write a Pandas program to use a dictionary in groupby to apply sum to one column and mean to another, then merge the outputs.
Write a Pandas program to group a DataFrame and pass a dictionary of custom functions to different columns for tailored analysis.
Write a Pandas program to use groupby with a dictionary mapping column names to aggregation functions and then rename the resulting columns.

Python Code Editor:

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