Crispo - Excel Challenge 31 2024

excel-challenges
weekly-exercises
Easy Sunday Excel Challenge
Published

August 4, 2024

Illustration for Crispo - Excel Challenge 31 2024

Challenge Description

Easy Sunday Excel Challenge

⭐ Problem Solution Customers Date Repeat Customers Carl

Solutions

library(tidyverse)
library(readxl)

path = "files/Excel Challenge 4th August.xlsx"
input = read_excel(path, range = "B2:C8")
test  = read_excel(path, range = "E2:F5")

result = input %>%
  separate_rows(Customers, sep = "; ") %>%
  mutate(Customers = str_trim(Customers)) %>%
  mutate(count = n(), .by = c(Customers, Date)) %>%
  filter(count > 1) %>%
  distinct() %>%
  summarise(`Repeat Customers` = str_c(Customers, collapse = "; "), .by = Date)

identical(result, test)
# [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

    • Uses direct text-pattern extraction instead of manual cleanup

  • 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/Excel Challenge 4th August.xlsx"
input = pd.read_excel(path, usecols="B:C", skiprows = 1, nrows = 6)
test = pd.read_excel(path,  usecols="E:F", skiprows = 1, nrows= 3)
test.columns = test.columns.str.replace('.1', '')

result = input.copy()
result['Customers'] = result['Customers'].str.split('; ')
result = result.explode('Customers')
result['Customers'] = result['Customers'].str.strip()
result['count'] = result.groupby(['Customers', 'Date'])['Customers'].transform('count')
result = result[result['count'] > 1].drop_duplicates()
result = result.groupby('Date')['Customers'].apply(lambda x: '; '.join(x)).reset_index(name='Repeat Customers')

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 moderate:

  • It combines familiar Excel-style logic with at least one non-trivial reshape, grouping, or parsing step.

  • The answer depends on getting the output layout exactly right.