Omid - Challenge 235

data-challenges
advanced-exercises
🔰 Challenge 235:Filtering & Removing!
Published

March 24, 2026

Illustration for Omid - Challenge 235

Challenge Description

🔰 Challenge 235:Filtering & Removing!

Solutions

library(tidyverse)
library(readxl)

path = "files/200-299/235/CH-235 Filtering & Removing.xlsx"
input = read_excel(path, range = "B2:F7")
test = read_excel(path, range = "H2:H6")

result = input %>%
  pivot_longer(-1, values_to = "Value") %>%
  summarise(nums = toString(sort(Value, decreasing = TRUE)), .by = ID) %>%
  distinct(nums, .keep_all = TRUE) %>%
  select(ID)

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

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • Reshapes the data into the grain required by the task

    • Aggregates or ranks values at the relevant grouping level

  • 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 = "200-299/235/CH-235 Filtering & Removing.xlsx"
input = pd.read_excel(path, usecols="B:F", skiprows=1, nrows=5)
test = pd.read_excel(path, usecols="H", skiprows=1, nrows=4).rename(columns=lambda col: col.replace('.1', ''))

input_long = input.melt(id_vars=input.columns[0], value_name="Value")
grouped = input_long.groupby(input.columns[0])["Value"].apply(lambda x: ",".join(map(str, sorted(x, reverse=True))))
result = grouped.drop_duplicates().index.to_frame(index=False)


print(result.equals(test)) # True

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • Reshapes the data into the grain required by the task

    • 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 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.