#0186

Rolling Average Sales

MediumPandas25 min20 XP

Problem

Given date and sales columns, sort by date and add rolling_3_sales as the 3-row rolling mean with min_periods=1.

Why This Matters

Rolling features appear in forecasting, dashboards, anomaly checks, and behavior modeling.

Function Signature

def add_rolling_sales(df):

Examples

Example 1

Inputsales = 10, 20, 30, 40 by date

Outputrolling values 10, 15, 20, 30

The fourth row averages 20, 30, and 40.

Constraints

Return the exact requested result.
Handle common edge cases.
Keep the solution readable before optimizing.

CodePython

import pandas as pd

def add_rolling_sales(df):
    """
    Input example: sales = 10, 20, 30, 40 by date
    Return: rolling values 10, 15, 20, 30
    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 add_rolling_sales(df):
    """
    Input example: sales = 10, 20, 30, 40 by date
    Return: rolling values 10, 15, 20, 30
    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

Inputsales = 10, 20, 30, 40 by date

Expectedrolling values 10, 15, 20, 30

The fourth row averages 20, 30, and 40.

Hidden Test Categories

minimal inputrepeated valueslarger realistic input