Excel BI - Excel Challenge 892

excel-challenges

excel-formulas

🔰 Find the Quarter & Running total for each quarter.

Published

March 24, 2026

Illustration for Excel BI - Excel Challenge 892

Challenge Description

🔰 Find the Quarter & Running total for each quarter.

Solutions

library(tidyverse)
library(readxl)
library(lubridate)

path <- "Excel/800-899/892/892 Quarterly Running Total.xlsx"
input <- read_excel(path, range = "A2:D50")
test <- read_excel(path, range = "E2:F50")

result = input %>%
  mutate(
    Quarter = paste0("Q", ceiling(month(as.Date(Date)) / 3)),
    amount = Credit + Interest - Debit
  ) %>%
  mutate(RunningTotal = cumsum(amount), .by = Quarter) %>%
  select(Quarter, RunningTotal)

all.equal(test, result)
# [1] TRUE

Logic: Read the workbook ranges needed for the challenge; Derive the required intermediate columns; Aggregate or rank the data at the required grouping level.
Strengths: The code maps the workbook rule into a compact, reproducible pipeline.
Areas for Improvement: The solution assumes the workbook layout and selected ranges remain stable, so any structural change in the sheet would require small adjustments.
Gem: The elegant part is how little code is needed once the correct intermediate representation is chosen.

import pandas as pd

path = "Excel\\800-899\\892\\892 Quarterly Running Total.xlsx"
input = pd.read_excel(path, usecols="A:D", nrows = 50, skiprows = 1)
test = pd.read_excel(path, usecols="E:F", nrows = 50, skiprows = 1)

result = (
    input
    .assign(
        Quarter = lambda df: 'Q' + ((pd.to_datetime(df['Date']).dt.month - 1) // 3 + 1).astype(str),
        amount = lambda df: df['Credit'] + df['Interest'] - df['Debit']
    )
    .assign(
        RunningTotal = lambda df: df.groupby('Quarter')['amount'].cumsum()
    )
    [['Quarter', 'RunningTotal']]
)

print(result.equals(test))
# True

The Python version follows the same grouped logic and keeps the transformation explicit in a dataframe pipeline.

Difficulty Level

Easy / Medium

The business rule is clear, though the workbook still needs a few transformation steps to reach the expected output.