Omid - Challenge 382

data-challenges
advanced-exercises
🔰 Challenge 382: Filter!
Published

March 24, 2026

Illustration for Omid - Challenge 382

Challenge Description

🔰 Challenge 382: Filter!

Solutions

library(tidyverse)
library(readxl)

path <- "300-399/382/CH-382 Filter.xlsx"
input <- read_excel(path, range = "B3:B10")
test <- read_excel(path, range = "F3:F9")

is_valid = function(s) {
  nums = str_extract_all(s, "[1-9]")[[1]] %>% as.numeric()
  num_prod = prod(nums)
  num_sum = sum(nums)
  return(num_prod %% 4 == 0 || num_sum %% 3 == 0)
}

result = input %>%
  filter(map_lgl(ID, is_valid))

all.equal(result$ID, test$ID)
# [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
import re
from math import prod

path = "300-399/382/CH-382 Filter.xlsx"
input = pd.read_excel(path, usecols="B", skiprows=2, nrows=8)
test = pd.read_excel(path, usecols="F", skiprows=2, nrows=6)

def is_valid(s):
    nums = [int(d) for d in re.findall(r"[1-9]", str(s))]
    num_prod = prod(nums)
    num_sum = sum(nums)
    return num_prod % 4 == 0 or num_sum % 3 == 0

result = input[input["ID"].apply(is_valid)].reset_index(drop=True)

print(result["ID"].equals(test.iloc[:, 0]))
# True

  • Logic:

    • Reads the workbook ranges needed for the challenge

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

    • Applies the rule iteratively until the output stabilizes

  • 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.