Ruby® Notes for Professionals book

Content list
About
Chapter 1: Getting started with Ruby Language
Section 1.1: Hello World
Section 1.2: Hello World as a Self-Executable File—using Shebang (Unix-like operating systems only)
Section 1.3: Hello World from IRB
Section 1.4: Hello World without source files
Section 1.5: Hello World with tk
Section 1.6: My First Method
Chapter 2: Casting (type conversion)
Section 2.1: Casting to a Float
Section 2.2: Casting to a String
Section 2.3: Casting to an Integer
Section 2.4: Floats and Integers
Chapter 3: Operators
Section 3.1: Operator Precedence and Methods
Section 3.2: Case equality operator (===)
Section 3.3: Safe Navigation Operator
Section 3.4: Assignment Operators
Section 3.5: Comparison Operators
Chapter 4: Variable Scope and Visibility
Section 4.1: Class Variables
Section 4.2: Local Variables
Section 4.3: Global Variables
Section 4.4: Instance Variables
Chapter 5: Environment Variables
Section 5.1: Sample to get user profile path
Chapter 6: Constants
Section 6.1: Define a constant
Section 6.2: Modify a Constant
Section 6.3: Constants cannot be defined in methods
Section 6.4: Define and change constants in a class
Chapter 7: Special Constants in Ruby
Section 7.1: __FILE__
Section 7.2: __dir__
Section 7.3: $PROGRAM_NAME or $0
Section 7.4: $$
Section 7.5: $1, $2, etc
Section 7.6: ARGV or $*
Section 7.7: STDIN
Section 7.8: STDOUT
Section 7.9: STDERR
Section 7.10: $stderr
Section 7.11: $stdout
Section 7.12: $stdin
Section 7.13: ENV
Chapter 8: Comments
Section 8.1: Single & Multiple line comments
Chapter 9: Arrays
Section 9.1: Create Array of Strings
Section 9.2: Create Array with Array::new
Section 9.3: Create Array of Symbols
Section 9.4: Manipulating Array Elements
Section 9.5: Accessing elements
Section 9.6: Creating an Array with the literal constructor [ ]
Section 9.7: Decomposition
Section 9.8: Arrays union, intersection and dierence
Section 9.9: Remove all nil elements from an array with #compact
Section 9.10: Get all combinations / permutations of an array
Section 9.11: Inject, reduce
Section 9.12: Filtering arrays
Section 9.13: #map
Section 9.14: Arrays and the splat (*) operator
Section 9.15: Two-dimensional array
Section 9.16: Turn multi-dimensional array into a one-dimensional (flattened) array
Section 9.17: Get unique array elements
Section 9.18: Create Array of numbers
Section 9.19: Create an Array of consecutive numbers or letters
Section 9.20: Cast to Array from any object
Chapter 10: Multidimensional Arrays
Section 10.1: Initializing a 2D array
Section 10.2: Initializing a 3D array
Section 10.3: Accessing a nested array
Section 10.4: Array flattening
Chapter 11: Strings
Section 11.1: Dierence between single-quoted and double-quoted String literals
Section 11.2: Creating a String
Section 11.3: Case manipulation
Section 11.4: String concatenation
Section 11.5: Positioning strings
Section 11.6: Splitting a String
Section 11.7: String starts with
Section 11.8: Joining Strings
Section 11.9: String interpolation
Section 11.10: String ends with
Section 11.11: Formatted strings
Section 11.12: String Substitution
Section 11.13: Multiline strings
Section 11.14: String character replacements
Section 11.15: Understanding the data in a string
Chapter 12: DateTime
Section 12.1: DateTime from string
Section 12.2: New
Section 12.3: Add/subtract days to DateTime
Chapter 13: Time
Section 13.1: How to use the strftime method
Section 13.2: Creating time objects
Chapter 14: Numbers
Section 14.1: Converting a String to Integer
Section 14.2: Creating an Integer
Section 14.3: Rounding Numbers
Section 14.4: Even and Odd Numbers
Section 14.5: Rational Numbers
Section 14.6: Complex Numbers
Section 14.7: Converting a number to a string
Section 14.8: Dividing two numbers
Chapter 15: Symbols
Section 15.1: Creating a Symbol
Section 15.2: Converting a String to Symbol
Section 15.3: Converting a Symbol to String
Chapter 16: Comparable
Section 16.1: Rectangle comparable by area
Chapter 17: Control Flow
Section 17.1: if, elsif, else and end
Section 17.2: Case statement
Section 17.3: Truthy and Falsy values
Section 17.4: Inline if/unless
Section 17.5: while, until
Section 17.6: Flip-Flop operator
Section 17.7: Or-Equals/Conditional assignment operator (||=)
Section 17.8: unless
Section 17.9: throw, catch
Section 17.10: Ternary operator
Section 17.11: Loop control with break, next, and redo
Section 17.12: return vs. next: non-local return in a block
Section 17.13: begin, end
Section 17.14: Control flow with logic statements
Chapter 18: Methods
Section 18.1: Defining a method
Section 18.2: Yielding to blocks
Section 18.3: Default parameters
Section 18.4: Optional parameter(s) (splat operator)
Section 18.5: Required default optional parameter mix
Section 18.6: Use a function as a block
Section 18.7: Single required parameter
Section 18.8: Tuple Arguments
Section 18.9: Capturing undeclared keyword arguments (double splat)
Section 18.10: Multiple required parameters
Section 18.11: Method Definitions are Expressions
Chapter 19: Hashes
Section 19.1: Creating a hash
Section 19.2: Setting Default Values
Section 19.3: Accessing Values
Section 19.4: Automatically creating a Deep Hash
Section 19.5: Iterating Over a Hash
Section 19.6: Filtering hashes
Section 19.7: Conversion to and from Arrays
Section 19.8: Overriding hash function
Section 19.9: Getting all keys or values of hash
Section 19.10: Modifying keys and values
Section 19.11: Set Operations on Hashes
Chapter 20: Blocks and Procs and Lambdas
Section 20.1: Lambdas
Section 20.2: Partial Application and Currying
Section 20.3: Objects as block arguments to methods
Section 20.4: Converting to Proc
Section 20.5: Blocks
Chapter 21: Iteration
Section 21.1: Each
Section 21.2: Implementation in a class
Section 21.3: Iterating over complex objects
Section 21.4: For iterator
Section 21.5: Iteration with index
Section 21.6: Map
Chapter 22: Exceptions
Section 22.1: Creating a custom exception type
Section 22.2: Handling multiple exceptions
Section 22.3: Handling an exception
Section 22.4: Raising an exception
Section 22.5: Adding information to (custom) exceptions
Chapter 23: Enumerators
Section 23.1: Custom enumerators
Section 23.2: Existing methods
Section 23.3: Rewinding
Chapter 24: Enumerable in Ruby
Section 24.1: Enumerable module
Chapter 25: Classes
Section 25.1: Constructor
Section 25.2: Creating a class
Section 25.3: Access Levels
Section 25.4: Class Methods types
Section 25.5: Accessing instance variables with getters and setters
Section 25.6: New, allocate, and initialize
Section 25.7: Dynamic class creation
Section 25.8: Class and instance variables
Chapter 26: Inheritance
Section 26.1: Subclasses
Section 26.2: What is inherited?
Section 26.3: Multiple Inheritance
Section 26.4: Mixins
Section 26.5: Refactoring existing classes to use Inheritance
Chapter 27: method_missing
Section 27.1: Catching calls to an undefined method
Section 27.2: Use with block
Section 27.3: Use with parameter
Section 27.4: Using the missing method
Chapter 28: Regular Expressions and Regex Based Operations
Section 28.1: =~ operator
Section 28.2: Regular Expressions in Case Statements
Section 28.3: Groups, named and otherwise
Section 28.4: Quantifiers
Section 28.5: Common quick usage
Section 28.6: match? - Boolean Result
Section 28.7: Defining a Regexp
Section 28.8: Character classes
Chapter 29: File and I/O Operations
Section 29.1: Writing a string to a file
Section 29.2: Reading from STDIN
Section 29.3: Reading from arguments with ARGV
Section 29.4: Open and closing a file
Section 29.5: get a single char of input
Chapter 30: Ruby Access Modifiers
Section 30.1: Instance Variables and Class Variables
Section 30.2: Access Controls
Chapter 31: Design Patterns and Idioms in Ruby
Section 31.1: Decorator Pattern
Section 31.2: Observer
Section 31.3: Singleton
Section 31.4: Proxy
Chapter 32: Loading Source Files
Section 32.1: Require files to be loaded only once
Section 32.2: Automatically loading source files
Section 32.3: Loading optional files
Section 32.4: Loading files repeatedly
Section 32.5: Loading several files
Chapter 33: Thread
Section 33.1: Accessing shared resources
Section 33.2: Basic Thread Semantics
Section 33.3: Terminating a Thread
Section 33.4: How to kill a thread
Chapter 34: Range
Section 34.1: Ranges as Sequences
Section 34.2: Iterating over a range
Section 34.3: Range between dates
Chapter 35: Modules
Section 35.1: A simple mixin with include
Section 35.2: Modules and Class Composition
Section 35.3: Module as Namespace
Section 35.4: A simple mixin with extend
Chapter 36: Introspection in Ruby
Section 36.1: Introspection of class
Section 36.2: Lets see some examples
Chapter 37: Monkey Patching in Ruby
Section 37.1: Changing an existing ruby method
Section 37.2: Monkey patching a class
Section 37.3: Monkey patching an object
Section 37.4: Safe Monkey patching with Refinements
Section 37.5: Changing a method with parameters
Section 37.6: Adding Functionality
Section 37.7: Changing any method
Section 37.8: Extending an existing class
Chapter 38: Recursion in Ruby
Section 38.1: Tail recursion
Section 38.2: Recursive function
Chapter 39: Splat operator (*)
Section 39.1: Variable number of arguments
Section 39.2: Coercing arrays into parameter list
Chapter 40: JSON with Ruby
Section 40.1: Using JSON with Ruby
Section 40.2: Using Symbols
Chapter 41: Pure RSpec JSON API testing
Section 41.1: Testing Serializer object and introducing it to Controller
Chapter 42: Gem Creation/Management
Section 42.1: Gemspec Files
Section 42.2: Building A Gem
Section 42.3: Dependencies
Chapter 43: rbenv
Section 43.1: Uninstalling a Ruby
Section 43.2: Install and manage versions of Ruby with rbenv
Chapter 44: Gem Usage
Section 44.1: Installing ruby gems
Section 44.2: Gem installation from github/filesystem
Section 44.3: Checking if a required gem is installed from within code
Section 44.4: Using a Gemfile and Bundler
Section 44.5: Bundler/inline (bundler v1.10 and later)
Chapter 45: Singleton Class
Section 45.1: Introduction
Section 45.2: Inheritance of Singleton Class
Section 45.3: Singleton classes
Section 45.4: Message Propagation with Singleton Class
Section 45.5: Reopening (monkey patching) Singleton Classes
Section 45.6: Accessing Singleton Class
Section 45.7: Accessing Instance/Class Variables in Singleton Classes
Chapter 46: Queue
Section 46.1: Multiple Workers One Sink
Section 46.2: Converting a Queue into an Array
Section 46.3: One Source Multiple Workers
Section 46.4: One Source - Pipeline of Work - One Sink
Section 46.5: Pushing Data into a Queue - #push
Section 46.6: Pulling Data from a Queue - #pop
Section 46.7: Synchronization - After a Point in Time
Section 46.8: Merging Two Queues
Chapter 47: Destructuring
Section 47.1: Overview
Section 47.2: Destructuring Block Arguments
Chapter 48: Struct
Section 48.1: Creating new structures for data
Section 48.2: Customizing a structure class
Section 48.3: Attribute lookup
Chapter 49: Metaprogramming
Section 49.1: Implementing "with" using instance evaluation
Section 49.2: send() method
Section 49.3: Defining methods dynamically
Section 49.4: Defining methods on instances
Chapter 50: Dynamic Evaluation
Section 50.1: Instance evaluation
Section 50.2: Evaluating a String
Section 50.3: Evaluating Inside a Binding
Section 50.4: Dynamically Creating Methods from Strings
Chapter 51: instance_eval
Section 51.1: Instance evaluation
Section 51.2: Implementing with
Chapter 52: Message Passing
Section 52.1: Introduction
Section 52.2: Message Passing Through Inheritance Chain
Section 52.3: Message Passing Through Module Composition
Section 52.4: Interrupting Messages
Chapter 53: Keyword Arguments
Section 53.1: Using arbitrary keyword arguments with splat operator
Section 53.2: Using keyword arguments
Section 53.3: Required keyword arguments
Chapter 54: Truthiness
Section 54.1: All objects may be converted to booleans in Ruby
Section 54.2: Truthiness of a value can be used in if-else constructs
Chapter 55: Implicit Receivers and Understanding Self
Section 55.1: There is always an implicit receiver
Section 55.2: Keywords change the implicit receiver
Section 55.3: When to use self?
Chapter 56: Introspection
Section 56.1: View an object's methods
Section 56.2: View an object's Instance Variables
Section 56.3: View Global and Local Variables
Section 56.4: View Class Variables
Chapter 57: Refinements
Section 57.1: Monkey patching with limited scope
Section 57.2: Dual-purpose modules (refinements or global patches)
Section 57.3: Dynamic refinements
Chapter 58: Catching Exceptions with Begin / Rescue
Section 58.1: A Basic Error Handling Block
Section 58.2: Saving the Error
Section 58.3: Checking for Dierent Errors
Section 58.4: Retrying
Section 58.5: Checking Whether No Error Was Raised
Section 58.6: Code That Should Always Run
Chapter 59: Command Line Apps
Section 59.1: How to write a command line tool to get the weather by zip code
Chapter 60: IRB
Section 60.1: Starting an IRB session inside a Ruby script
Section 60.2: Basic Usage
Chapter 61: ERB
Section 61.1: Parsing ERB
Chapter 62: Generate a random number
Section 62.1: 6 Sided die
Section 62.2: Generate a random number from a range (inclusive)
Chapter 63: Getting started with Hanami
Section 63.1: About Hanami
Section 63.2: How to install Hanami?
Section 63.3: How to start the server?
Chapter 64: OptionParser
Section 64.1: Mandatory and optional command line options
Section 64.2: Default values
Section 64.3: Long descriptions
Chapter 65: Operating System or Shell commands
Section 65.1: Recommended ways to execute shell code in Ruby:
Section 65.2: Clasic ways to execute shell code in Ruby:
Chapter 66: C Extensions
Section 66.1: Your first extension
Section 66.2: Working with C Structs
Section 66.3: Writing Inline C - RubyInLine
Chapter 67: Debugging
Section 67.1: Stepping through code with Pry and Byebug
Chapter 68: Ruby Version Manager
Section 68.1: How to create gemset
Section 68.2: Installing Ruby with RVM
Appendix A: Installation
Section A.1: Installing Ruby macOS
Section A.2: Gems
Section A.3: Linux - Compiling from source
Section A.4: Linux—Installation using a package manager
Section A.5: Windows - Installation using installer
Section A.6: Linux - troubleshooting gem install
Credits
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