Crispo - Excel Challenge 30 2025

excel-challenges
weekly-exercises
Easy Sunday Excel Challenge
Published

July 27, 2025

Illustration for Crispo - Excel Challenge 30 2025

Challenge Description

Easy Sunday Excel Challenge

⭐ Requirements New Purchase Day1 Day2 Day3 Day4

Solutions

library(tidyverse)
library(readxl)

path = "files/2025-07-27/CSEC 27072025.xlsx"
input = read_excel(path, range = "B3:N3", col_names = FALSE) %>% t() %>% data.frame(Requirements = .)
test  = read_excel(path, range = "B4:N4", col_names = FALSE) %>% t() %>% data.frame(Test = .)

result = input %>%
  mutate(`New Purchase` = pmax(Requirements - lag(cummax(Requirements),1, default = 0),0))

all.equal(result$`New Purchase`, test$Test, check.attributes = FALSE) 
# > [1] TRUE

  • Logic:

    • Reads the workbook range needed for the challenge

    • Builds the intermediate helper columns that drive the final answer

  • Strengths:

    • The R solution stays compact and mirrors the workbook logic closely.

  • Areas for Improvement:

    • The code assumes the workbook layout and named ranges remain stable.

  • Gem:

    • The best part of the solution is choosing a tidy intermediate shape before producing the final answer.
import pandas as pd

path = "files/2025-07-27/CSEC 27072025.xlsx"
input = pd.read_excel(path, usecols="B:N", skiprows=1, nrows=3)
requirements = input.iloc[0].to_frame('Requirements')
test = input.iloc[1].to_frame('Test')
requirements['New Purchase'] = (req := requirements['Requirements']).sub(req.cummax().shift(fill_value=0)).clip(lower=0)

print(all(test['Test'] == requirements['New Purchase'])) # True

  • Logic:

    • Reads the workbook range needed for the challenge

  • Strengths:

    • The Python version keeps the same rule in a direct pandas-oriented workflow.

  • Areas for Improvement:

    • As with the R version, any workbook layout change would require small adjustments.

  • Gem:

    • The implementation stays close to the stated challenge instead of adding unnecessary complexity.

Difficulty Level

This task is easy to moderate:

  • The business rule is readable, but the workbook still needs a few careful transformation steps.