Ruby Documentation
Master Ruby's documentation system and learn how to find help, understand method signatures, and explore the Ruby ecosystem effectively.
Built-in Documentation Tools
ri (Ruby Information): Command-line tool for viewing Ruby documentation
ri Command
Basic ri Usage
# Get help for a method
ri String#upcase
# Get help for a class
ri Array
# Search for methods
ri -T upcase
# List all classes
ri -l
Example ri Output
$ ri String#upcase
= String#upcase
(from ruby core)
=== Implementation from String
------------------------------------------------------------------------------
str.upcase -> new_str
Returns a copy of str with all lowercase letters replaced with their
uppercase counterparts.
Getting Help in IRB
IRB Help Commands
irb(main):001:0> help
irb(main):002:0> "hello".methods
irb(main):003:0> "hello".method(:upcase)
irb(main):004:0> "hello".method(:upcase).source_location
Online Documentation Resources
Official Ruby Documentation
- ruby-doc.org - Core Ruby API
- docs.ruby-lang.org - Official guides
- ruby-lang.org - Main Ruby website
Features
- Complete API reference
- Method signatures
- Code examples
- Version-specific docs
Community Resources
- APIDock - Enhanced Ruby docs
- Ruby API - Modern Ruby docs
- Stack Overflow - Q&A
Features
- User comments
- Better search
- Modern interface
- Community examples
How to Read Ruby Documentation
Understanding Method Signatures
Method Signature Breakdown
str.gsub(pattern, replacement) → new_str
│ │ │ │ └─ Return type
│ │ │ └─ Parameter name
│ │ └─ Parameter name
│ └─ Method name
└─ Object type
Common Notation
→- Returns?- Boolean return (true/false)!- Modifies the object*- Variable arguments=- Default parameter value
Gem Documentation
Finding Gem Documentation
Using gem server
# Start gem documentation server
gem server
# Visit http://localhost:8808 in your browser
# Browse all installed gems
Online Gem Resources
- RubyGems.org - Gem repository
- GitHub - Source code and README
- RubyDoc.info - Gem documentation
Documentation Best Practices
Effective Documentation Reading
- Start with examples: Look for code examples first
- Read method signatures: Understand parameters and return values
- Check related methods: Explore similar methods in the same class
- Use IRB to test: Try examples in IRB to understand behavior
- Bookmark useful docs: Keep links to frequently used documentation
Common Documentation Mistakes
- Not reading the full description: Skim through important details
- Ignoring parameter types: Don't check what types of arguments are expected
- Not testing examples: Don't verify examples in IRB
- Overlooking edge cases: Miss important behavior notes
What's Next?
Continue Your Ruby Journey
- Practice with ri: Use ri command to explore Ruby methods
- Bookmark resources: Save useful documentation links
- Learn Variables: Understand different types of variables
- Explore Data Types: Master strings, numbers, arrays, and hashes
- Study Methods: Learn how to define and use methods