18. Generate Markdown Table from CSV Data
1. Hello, World!
2. Rename Photos by Capture Date
3. Organize Downloads Folder by File Type
4. Delete Old Log Files Automatically
5. Find Duplicate Files Using MD5 Hashing
6. Generate Comprehensive File Inventory
7. Parse Web Server Logs for Performance Metrics
8. Extract Emails, URLs, and Phone Numbers from Text
9. Track Daily and Monthly Active Users from Apache Logs
10. Generate Formatted Text Reports with Column Alignment
11. Analyze Sales Transactions and Generate Revenue Reports
12. Clean and Validate CSV Data
13. Convert JSON API Responses to CSV
14. Parse and Validate Configuration Files
15. Build a CLI Calculator with Argument Parsing
16. Parse and Display Weather Data from JSON
17. Build a Simple Inventory System with Classes
18. Generate Markdown Table from CSV Data
19. Aggregate Sales Data by Time Period
20. Recursive Directory Size Calculator with Filtering
21. Parse and Transform Server Configuration
22. Find and Replace Across Multiple Files
23. Build a Simple Template Engine
24. CSV Data Validator with Business Rules
25. Build a Multi-Format Log Analyzer

Challenge

Problem

Documentation is critical in software development, and markdown is the universal format for READMEs, wikis, and documentation sites. This drill teaches you to read CSV data and transform it into properly formatted markdown tables with alignment, padding, and separators. You'll learn markdown table syntax, dynamic column width calculation, string alignment techniques, and text formatting—skills essential for generating documentation, reports, and developer tools. Note: This drill parses CSV manually using string methods rather than Ruby's CSV library.

Difficulty: Beginner

Instructions

  1. Read CSV file with headers
  2. Calculate the maximum width needed for each column (including header)
  3. Generate markdown table with:
    • Header row with column names
    • Separator row with dashes (e.g., | --- | --- |)
    • Data rows with values
  4. Pad all cells to their column's maximum width
  5. Left-align text columns, right-align number columns
  6. Return the markdown table as a string
  7. Print confirmation: 'Markdown table generated: X rows, Y columns'

Files

Editable
Read-only

Hints

Hint 1

Parse CSV manually: line.split(',')

Hint 2

First row is headers, remaining rows are data

Hint 3

Calculate max width: array.map(&:length).max

Hint 4

Use map.with_index to iterate with column index

Hint 5

string.ljust(width) pads right, string.rjust(width) pads left

Hint 6

Check if numeric: string.match?(/^\d+\.?\d*$/)

Hint 7

Join array with separator: array.join(' | ')

Ruby 3.4

Provided Files (Read-only)

1. Correct confirmation message

Input: 
generate_markdown_table('data.csv')
Expected Output: 
Markdown table generated: 4 rows, 4 columns

2. Header row formatted correctly

Input: 
md = generate_markdown_table('data.csv')
puts md.lines.first
Expected Output: 
Markdown table generated: 4 rows, 4 columns
| Name  | Department  | Salary | Years |

3. Separator row has dashes

Input: 
md = generate_markdown_table('data.csv')
puts md.lines[1]
Expected Output: 
Markdown table generated: 4 rows, 4 columns
| ----- | ----------- | ------ | ----- |
+ 2 hidden test cases