Omid - Challenge 269

data-challenges
advanced-exercises
🔰 In the Question table, transform each text entry by inserting a hyphen (‘-’) between every character.
Published

March 24, 2026

Illustration for Omid - Challenge 269

Challenge Description

🔰 In the Question table, transform each text entry by inserting a hyphen (“-”) between every character.

Solutions

library(tidyverse)
library(readxl)

path = "files/200-299/269/CH-269 Text Cleaning.xlsx"
input = read_excel(path, range = "B2:B9")
test  = read_excel(path, range = "D2:D9")

result = input %>%
  mutate(ID = str_replace_all(str_remove_all(ID, "-"), "(.)(?=.)", "\\1-"))

all.equal(result$ID, test$`ID 1`, check.attributes = FALSE)
# > [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 = "200-299/269/CH-269 Text Cleaning.xlsx"
input = pd.read_excel(path, usecols="B", skiprows=1, nrows=8)
test = pd.read_excel(path, usecols="D", skiprows=1, nrows=8)

input["ID 1"] = ["-".join(c for c in name if c != "-") for name in input["ID"]]

print(input["ID 1"].equals(test["ID 1"])) # 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 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.