Omid - Challenge 332

data-challenges
advanced-exercises
🔰 Calculate the End Date by adding the Duration to the Start Date/Time.
Published

March 24, 2026

Illustration for Omid - Challenge 332

Challenge Description

🔰 Calculate the End Date by adding the Duration to the Start Date/Time.

Solutions

library(tidyverse)
library(readxl)

path <- "300-399/332/CH-332 Date Calculation.xlsx"
input <- read_excel(path, range = "B2:C8")
test <- read_excel(path, range = "D2:D8") %>%
  mutate(`End Time` = dmy_hms(`End Time`))

result = input %>%
  mutate(`Start Date` = dmy_hms(`Start Date`)) %>%
  mutate(`End Date` = `Start Date` + hours(as.numeric(`Duration [h]`)))

all.equal(result$`End Date`, test$`End Time`)
# First time incorrect in the Excel file, others correct

  • 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 datetime import timedelta

path = "300-399/332/CH-332 Date Calculation.xlsx"
input = pd.read_excel(path, usecols="B:C", skiprows=1, nrows=7)
test = pd.read_excel(path, usecols="D", skiprows=1, nrows=7)
test['End Time'] = pd.to_datetime(test['End Time'] , format="%d/%m/%Y - %H:%M:%S")

input['Start Date'] = pd.to_datetime(input['Start Date'], format="%d/%m/%Y - %H:%M:%S")
# durarion + start date
input['Calculated End Date'] = input.apply(lambda row: row['Start Date'] + timedelta(hours=row['Duration [h]']), axis=1)

print(input['Calculated End Date'].equals(test['End Time']))  # First entry wrong

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