#0136

Top N Rows Per Group

MediumPandas25 min20 XP

Problem

Given a DataFrame with group and score, return the top n rows per group sorted by group then score descending.

Why This Matters

Top-N per group appears in recommendations, leaderboards, best products by category, and model diagnostics.

Function Signature

def top_n_per_group(df, n):

Examples

Example 1

InputA scores 5,9; B scores 2,8; n=1

OutputA 9 and B 8

Each group contributes its own best row.

Constraints

Return the exact requested structure.
Handle normal edge cases cleanly.
Prefer readable code over clever shortcuts.

CodePython

import pandas as pd

def top_n_per_group(df, n):
    """
    Input example: A scores 5,9; B scores 2,8; n=1
    Return: A 9 and B 8
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return df

import pandas as pd

def top_n_per_group(df, n):
    """
    Input example: A scores 5,9; B scores 2,8; n=1
    Return: A 9 and B 8
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return df

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

InputA scores 5,9; B scores 2,8; n=1

ExpectedA 9 and B 8

Each group contributes its own best row.

Hidden Test Categories

n larger than group sizetiessingle group