Omid - Challenge 351

data-challenges
advanced-exercises
🔰 Challenge 351: Filter!
Published

March 24, 2026

Illustration for Omid - Challenge 351

Challenge Description

🔰 Challenge 351: Filter!

Solutions

library(tidyverse)
library(readxl)

path <- "300-399/351/CH-351 Filter.xlsx"
input <- read_excel(path, range = "B3:B10")
test <- read_excel(path, range = "F3:F6")

result = input %>%
  filter(str_detect(ID, "M.*N.*M.*"))

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

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • 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 = "300-399/351/CH-351 Filter.xlsx"
input_data = pd.read_excel(path, usecols="B", skiprows=2, nrows=8)
test_data = pd.read_excel(path, usecols="F", skiprows=2, nrows=3).rename(columns=lambda x: x.rstrip('.1'))

result = input_data[input_data.iloc[:, 0].str.contains(r"M.*N.*M.*", na=False)].reset_index(drop=True)

print(result.equals(test_data)) # 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.