Omid - Challenge 385

data-challenges
advanced-exercises
🔰 Result Question Total Sales Product ID Date Customer ID XNM-13 XNM-07
Published

March 24, 2026

Illustration for Omid - Challenge 385

Challenge Description

🔰 Result Question Total Sales Product ID Date Customer ID XNM-13 XNM-07

Solutions

library(tidyverse)
library(readxl)

path <- "300-399/385/CH-385 Replacement.xlsx"
input <- read_excel(path, range = "B3:E10")
test <- read_excel(path, range = "G3:J10")

result <- input |>
  mutate(
    `Customer ID` = if_else(
      Date >= as.POSIXct("2024-08-14"),
      str_replace(`Customer ID`, "X", "C"),
      `Customer ID`
    )
  )

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

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • Builds the intermediate columns that drive the final result

    • Parses the text patterns directly instead of relying on manual cleanup

  • 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 = "300-399/385/CH-385 Replacement.xlsx"
input = pd.read_excel(path, usecols="B:E", skiprows=2, nrows=7)
test  = pd.read_excel(path, usecols="G:J", skiprows=2, nrows=7).rename(columns=lambda c: __import__("re").sub(r"\.\d+$", "", c))

result = input.copy()
mask = result["Date"] >= pd.Timestamp("2024-08-14")
result.loc[mask, "Customer ID"] = result.loc[mask, "Customer ID"].str.replace("X", "C", n=1)

print((result == test).all().all())
## Output: True

  • Logic:

    • Reads the workbook ranges needed for the challenge

  • 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 core logic is clear, but the correct transformation pattern is not obvious from the raw input.

  • The challenge combines multiple reshaping, grouping, or parsing steps.