#0112

Top N Records by Key

EasyPython15 min10 XP

Problem

Given a list of dictionaries, key, and n, return the top n records sorted by key descending. Do not mutate the input list.

Why This Matters

Top-N queries show up everywhere: leaderboards, recommendations, highest revenue products, and model error analysis.

Function Signature

def top_n(records, key, n):

Examples

Example 1

Input[{"name":"A","score":5},{"name":"B","score":9}], "score", 1

Output[{"name":"B","score":9}]

The highest score record comes first.

Constraints

Return the requested value exactly.
Handle the stated edge cases.
Keep the solution readable.

CodePython

def top_n(records, key, n):
    """
    Input example: [{"name":"A","score":5},{"name":"B","score":9}], "score", 1
    Return: [{"name":"B","score":9}]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

def top_n(records, key, n):
    """
    Input example: [{"name":"A","score":5},{"name":"B","score":9}], "score", 1
    Return: [{"name":"B","score":9}]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

Input[{"name":"A","score":5},{"name":"B","score":9}], "score", 1

Expected[{"name":"B","score":9}]

The highest score record comes first.

Hidden Test Categories

n larger than recordsn equals zeroties keep sorted stability