Omid - Challenge 348

data-challenges
advanced-exercises
🔰 Challenge 348: Filter!
Published

March 24, 2026

Illustration for Omid - Challenge 348

Challenge Description

🔰 Challenge 348: Filter!

Solutions

library(tidyverse)
library(readxl)
library(charcuterie)

path <- "300-399/348/CH-348 Filter.xlsx"
input <- read_excel(path, range = "B3:B10")
test <- read_excel(path, range = "F3:F6")

result = input %>%
  mutate(chars = map(ID, chars)) %>%
  mutate(char_counts = map(chars, ~ table(.))) %>%
  filter(map_lgl(char_counts, ~ any(. >= 3))) %>%
  select(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

  • 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
from collections import Counter

path = "300-399/348/CH-348 Filter.xlsx"
input = pd.read_excel(path, usecols="B", skiprows=2, nrows=8)
test = pd.read_excel(path, usecols="F", skiprows=2, nrows=3).rename(columns=lambda col: col.replace('.1', ''))

def has_char_at_least_3(s):
    counts = Counter(str(s))
    return any(v >= 3 for v in counts.values())

result = input[input['ID'].apply(has_char_at_least_3)].reset_index(drop=True)

print(result.equals(test)) # True

  • Logic:

    • Reads the workbook ranges needed for the challenge

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