Crispo - Excel Challenge 02 2025

excel-challenges
weekly-exercises
Easy Sunday Excel Challenge
Published

January 12, 2025

Illustration for Crispo - Excel Challenge 02 2025

Challenge Description

Easy Sunday Excel Challenge

⭐ ⭐Group the customers per month

Solutions

library(tidyverse)
library(readxl)

path = "files/Ex-Challenge 02 2025.xlsx"
input = read_excel(path, range = "B2:C14")
test  = read_excel(path, range = "E2:F7")

result = input %>%
  mutate(Month = format(Date, "%B"),
         M = month(Date),
         D = day(Date)) %>%
  arrange(M, D) %>%
  summarise(Month = first(Month), 
            Customers = paste0(Customer, collapse = ","),
            .by = M) %>%
  select(-M)

all.equal(result, test, check.attributes = FALSE)
#> [1] TRUE

  • Logic:

    • Reads the workbook range needed for the challenge

    • Aggregates or ranks values at the correct grouping level

    • 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/Ex-Challenge 02 2025.xlsx"
input = pd.read_excel(path, usecols="B:C", skiprows=1, nrows=12)
test = pd.read_excel(path, usecols="E:F", skiprows=1, nrows=5)

input['Month'] = input['Date'].dt.strftime('%B')
input['M'] = input['Date'].dt.month
input['D'] = input['Date'].dt.day

result = (input.sort_values(['M', 'D'])
          .groupby('M')
          .agg(Month=('Month', 'first'),
               Customers=('Customer', ','.join))
          .reset_index(drop=True))

print(result.equals(test))
# True

  • Logic:

    • Reads the workbook range needed for the challenge

    • Aggregates or ranks values at the correct grouping level

  • 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.