Omid - Challenge 87

data-challenges
advanced-exercises
🔰 From Date Product Price A B Date Quantity Question Table: Price List
Published

March 24, 2026

Illustration for Omid - Challenge 87

Challenge Description

🔰 From Date Product Price A B Date Quantity Question Table: Price List

Solutions

library(tidyverse)
library(readxl)
library(fuzzyjoin)

path = "files/CH-087 Price List.xlsx"
input1 = read_excel(path, range = "B2:D9")
input2 = read_excel(path, range = "G2:I11")
test = read_excel(path, range = "J2:J11")

result = input2  %>%
  fuzzy_left_join(input1, by = c("Product" = "Product", "Date" = "From Date"),
                  match_fun = list(`==`, `>=`)) %>%
  filter(`From Date` == max(`From Date`), .by = c("Product.x", "Date"))

identical(result$Price, test$Price)
# [1] TRUE

  • Logic:

    • Reads the workbook ranges needed for the challenge

  • Strengths:

    • The R solution stays close to the workbook rule and keeps the transformation compact.

  • Areas for Improvement:

    • The code assumes the sheet structure and source ranges remain stable.

  • Gem:

    • The strongest part of the solution is choosing the right intermediate representation before shaping the final output.
import pandas as pd

path = 'CH-087 Price List.xlsx'
input1 = pd.read_excel(path, usecols= "B:D", skiprows= 1, nrows = 7)
input2 = pd.read_excel(path, usecols= "G:I", skiprows= 1, nrows = 9)
input2.columns = input2.columns.str.replace(".1", "")
test = pd.read_excel(path, usecols= "J", skiprows= 1, nrows = 9)
test.columns = test.columns.str.replace(".1", "")

result = input2.merge(input1, on = "Product", how = "left")\
    .loc[lambda df: df['Date'] >= df['From Date']]\
    .groupby(['Product', 'Date']).max()\
    .sort_values(by = ['Date'], ascending = [True])\
    .reset_index()
    
print(result["Price"].equals(test["Price"])) # True

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • Aggregates or ranks values at the relevant grouping level

  • Strengths:

    • The Python version follows the same rule in a direct dataframe-oriented implementation.

  • Areas for Improvement:

    • The code assumes the workbook layout remains stable, so any sheet redesign would require small adjustments.

  • Gem:

    • The implementation stays close to the original workbook rule instead of adding unnecessary abstraction.

Difficulty Level

This task is moderate:

  • The business rule is readable, but the workbook still requires careful implementation to reach the expected layout.