Head First Ruby. A Brain-Friendly Guide

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• Head First Ruby
• Dedication
• Author of Head First Ruby
• How to Use This Book: Intro
  • Who is this book for?
    • Who should probably back away from this book?
  • We know what youre thinking
  • We know what your brain is thinking
  • Metacognition: thinking about thinking
  • Heres what WE did
  • Heres what YOU can do to bend your brain into submission
  • Read me
  • Acknowledgments
  • Safari Books Online
• 1. More with Less: Code the Way You Want
  • The Ruby philosophy
  • Get Ruby
  • Use Ruby
  • Use Rubyinteractively
    • Using the irb shell
  • Your first Ruby expressions
  • Math operations and comparisons
  • Strings
  • Variables
  • Everything is an object!
  • Calling a method on an object
  • Lets build a game
  • Input, storage, and output
  • Running scripts
  • Comments
  • puts and print
  • Method arguments
  • gets
  • Parentheses are optional on method calls
  • String interpolation
  • Whats in that string?
  • Inspecting objects with the inspect and p methods
  • Escape sequences in strings
    • Commonly used escape sequences
  • Calling chomp on the string object
  • What methods are available on an object?
  • Generating a random number
  • Converting to strings
  • Ruby makes working with strings easy
  • Converting strings to numbers
    • Common conversions
  • Conditionals
  • The opposite of if is unless
  • Loops
  • Lets try running our game!
  • Your Ruby Toolbox
  • Up Next...
• 2. Methods and Classes: Getting Organized
  • Defining methods
  • Calling methods youve defined
  • Method names
  • Parameters
  • Optional parameters
  • Return values
    • Implicit return values
  • Returning from a method early
  • Some messy methods
  • Too many arguments
  • Too many if statements
  • Designing a class
  • Whats the difference between a class and an object?
  • Your first class
  • Creating new instances (objects)
  • Breaking up our giant methods into classes
    • The object-oriented approach
  • Creating instances of our new animal classes
  • Updating our class diagram with instance methods
  • Our objects dont know their names or ages!
  • Too many arguments (again)
  • Local variables live until the method ends
  • Instance variables live as long as the instance does
  • Encapsulation
  • Attribute accessor methods
  • Using accessor methods
  • Attribute writers and readers
    • Symbols
  • Attribute writers and readers in action
  • Ensuring data is valid with accessors
  • Errorsthe emergency stop button
  • Using raise in our attribute writer methods
  • Our complete Dog class
  • Your Ruby Toolbox
  • Up Next...
• 3. Inheritance: Relying on Your Parents
  • Copy, paste... Such a waste...
  • Mikes code for the virtual test-drive classes
  • Inheritance to the rescue!
  • Defining a superclass (requires nothing special)
  • Defining a subclass (is really easy)
  • Adding methods to subclasses
  • Subclasses keep inherited methods alongside new ones
  • Instance variables belong to the object, not the class!
  • Overriding methods
  • Bringing our animal classes up to date with inheritance
  • Designing the animal class hierarchy
  • Code for the Animal class and its subclasses
  • Overriding a method in the Animal subclasses
  • We need to get at the overridden method!
  • The super keyword
  • A super-powered subclass
  • Difficulties displaying Dogs
  • The Object class
  • Why everything inherits from the Object class
  • Overriding the inherited method
  • Your Ruby Toolbox
  • Up Next...
• 4. Initializing Instances: Off to a Great Start
  • Payroll at Chargemore
  • An Employee class
  • Creating new Employee instances
  • A division problem
  • Division with Rubys Fixnum class
  • Division with Rubys Float class
  • Fixing the salary rounding error in Employee
  • Formatting numbers for printing
  • Format sequences
  • Format sequence types
  • Format sequence width
  • Format sequence width with floating-point numbers
  • Using format to fix our pay stubs
  • When we forget to set an objects attributes...
  • nil stands for nothing
  • / is a method
  • The initialize method
  • Employee safety with initialize
  • Arguments to initialize
  • Using optional parameters with initialize
  • initialize does an end-run around our validation
  • initialize and validation
  • Call other methods on the same instance with self
  • When self is optional
  • Implementing hourly employees through inheritance
  • Restoring initialize methods
  • Inheritance and initialize
  • super and initialize
  • Same class, same attribute values
  • An inefficient factory method
  • Class methods
  • Our complete source code
  • Your Ruby Toolbox
  • Up Next...
• 5. Arrays and Blocks: Better Than Loops
  • Arrays
  • Accessing arrays
  • Arrays are objects, too!
  • Looping over the items in an array
  • The repeating loop
  • Eliminating repetition...the WRONG way...
  • Chunks of code?
  • Blocks
    • Blocks are mind-bending stuff. But stick with it!
  • Defining a method that takes blocks
  • Your first block
  • Flow of control between a method and block
  • Calling the same method with different blocks
  • Calling a block multiple times
  • Block parameters
  • Using the yield keyword
  • Block formats
  • The each method
  • The each method, step-by-step
  • DRYing up our code with each and blocks
  • Blocks and variable scope
  • Using each with the refund method
  • Using each with our last method
  • Our complete invoicing methods
  • Weve gotten rid of the repetitive loop code!
  • Utilities and appliances, blocks and methods
  • Your Ruby Toolbox
  • Up Next...
• 6. Block Return Values: How Should I Handle This?
  • A big collection of words to search through
  • Opening the file
  • Safely closing the file
  • Safely closing the file, with a block
  • Dont forget about variable scope!
  • Finding array elements we want, with a block
  • The verbose way to find array elements, using each
  • Introducing a faster method...
  • Blocks have a return value
  • How the method uses a block return value
  • Putting it all together
  • A closer look at the block return values
  • Eliminating elements we dont want, with a block
  • The return values for reject
  • Breaking a string into an array of words
  • Finding the index of an array element
  • Making one array thats based on another, the hard way
  • Making one array based on another, using map
  • Some additional logic in the map block body
  • The finished product
  • Your Ruby Toolbox
  • Up Next...
• 7. Hashes: Labeling Data
  • Counting votes
  • An array of arrays...is not ideal
  • Hashes
  • Hashes are objects
  • Hashes return nil by default
  • nil (and only nil) is falsy
  • Returning something other than nil by default
  • Normalizing hash keys
  • Hashes and each
  • A mess of method arguments
  • Using hashes as method parameters
  • Hash parameters in our Candidate class
  • Leave off the braces!
  • Leave out the arrows!
  • Making the entire hash optional
  • Typos in hash arguments are dangerous
  • Keyword arguments
  • Using keyword arguments with our Candidate class
  • Required keyword arguments
  • Your Ruby Toolbox
  • Up Next...
• 8. References: Crossed Signals
  • Some confusing bugs
  • The heap
  • References
  • When references go wrong
  • Aliasing
  • Fixing the astronomers program
  • Quickly identifying objects with inspect
  • Problems with a hash default object
  • Were actually modifying the hash default object!
  • A more detailed look at hash default objects
  • Back to the hash of planets and moons
  • Our wish list for hash defaults
  • Hash default blocks
  • Hash default blocks: Assigning to the hash
  • Hash default blocks: Block return value
  • Hash default blocks: A shortcut
  • The astronomers hash: Our final code
  • Using hash default objects safely
  • Hash default object rule #1: Dont modify the default object
  • Hash default object rule #2: Assign values to the hash
  • The rule of thumb for hash defaults
  • Your Ruby Toolbox
  • Up Next...
• 9. Mixins: Mix It Up
  • The media-sharing app
  • The media-sharing app...using inheritance
  • One of these classes is not (quite) like the others
  • Option one: Make Photo a subclass of Clip
  • Option two: Copy the methods you want into the Photo class
  • Not an option: Multiple inheritance
  • Using modules as mixins
  • Mixins, behind the scenes
  • Creating a mixin for comments
  • Using our comments mixin
  • A closer look at the revised comments method
  • Why you shouldnt add initialize to a mixin
  • Mixins and method overriding
  • Avoid using initialize methods in modules
  • Using the Boolean or operator for assignment
  • The conditional assignment operator
  • Our complete code
  • Your Ruby Toolbox
  • Up Next...
• 10. Comparable and Enumerable: Ready-Made Mixes
  • Mixins built into Ruby
  • A preview of the Comparable mixin
  • Choice (of) beef
  • Implementing a greater-than method on the Steak class
  • Constants
  • We have a lot more methods to define...
  • The Comparable mixin
  • The spaceship operator
  • Implementing the spaceship operator on Steak
  • Mixing Comparable into Steak
  • How the Comparable methods work
  • Our next mixin
  • The Enumerable module
  • A class to mix Enumerable into
  • Mixing Enumerable into our class
  • Inside the Enumerable module
  • Your Ruby Toolbox
  • Up Next...
• 11. Documentation: Read the Manual
  • Learning how to learn more
  • Rubys core classes and modules
  • Documentation
  • HTML documentation
  • Listing available classes and modules
  • Looking up instance methods
  • Instance methods denoted with # in the docs
  • Instance method documentation
  • Arguments in call signatures
  • Blocks in call signatures
  • Read the docs for the superclass and mixins, too!
  • Read the docs for the superclass and mixins, too! (continued)
  • Pool Puzzle
  • Pool Puzzle Solution
  • Looking up class methods
  • Class method documentation
  • Docs for a class that doesnt exist?!
  • The Ruby standard library
  • Looking up classes and modules in the standard library
  • Where Ruby docs come from: rdoc
  • What rdoc can deduce about your classes
  • Adding your own documentation, with comments
  • The initialize instance method appears as the new class method
  • Your Ruby Toolbox
  • Up Next...
• 12. Exceptions: Handling the Unexpected
  • Dont use method return values for error messages
  • Using raise to report errors
  • Using raise by itself creates new problems
  • Exceptions: When somethings gone wrong
  • Rescue clauses: A chance to fix the problem
  • Rubys search for a rescue clause
  • Using a rescue clause with our SmallOven class
  • We need a description of the problem from its source
  • Exception messages
  • Our code so far...
  • Different rescue logic for different exceptions
  • Exception classes
  • Specifying exception class for a rescue clause
  • Multiple rescue clauses in one begin/end block
  • Updating our oven code with custom exception classes
  • Trying again after an error with retry
  • Updating our oven code with retry
  • Things you want to do no matter what
  • The ensure clause
  • Ensuring the oven gets turned off
  • Your Ruby Toolbox
  • Up Next...
• 13. Unit Testing: Code Quality Assurance
  • Automated tests find your bugs before someone else does
  • A program we should have had automated tests for
  • Types of automated tests
  • MiniTest: Rubys standard unit-testing library
  • Running a test
  • Testing a class
  • A closer look at the test code
  • Red, green, refactor
  • Tests for ListWithCommas
  • Getting the test to pass
  • Another bug to fix
  • Test failure messages
  • A better way to assert that two values are equal
  • Some other assertion methods
  • Removing duplicated code from your tests
  • The setup method
  • The teardown method
  • Updating our code to use the setup method
  • Your Ruby Toolbox
  • Up Next...
• 14. Web Apps: Serving HTML
  • Writing web apps in Ruby
  • Our task list
  • Project directory structure
  • Browsers, requests, servers, and responses
  • Sinatra takes requests
  • Downloading and installing libraries with RubyGems
  • Installing the Sinatra gem
  • A simple Sinatra app
  • Your computer is talking to itself
  • Request type
  • Resource path
  • Sinatra routes
  • Multiple routes in the same Sinatra app
  • A route for the list of movies
  • Making a movie list in HTML
  • Accessing the HTML from Sinatra
  • A class to hold our movie data
  • Setting up a Movie object in the Sinatra app
  • ERB embedding tags
  • The ERB output embedding tag
  • Embedding a movie title in our HTML
  • Pool Puzzle
  • Pool Puzzle Solution
  • The regular embedding tag
  • Looping over several movie titles in our HTML
  • Letting users add data with HTML forms
  • Getting an HTML form for adding a movie
  • HTML tables
  • Cleaning up our form with an HTML table
  • Theres still more to do
  • Your Ruby Toolbox
  • Up Next...
• 15. Saving and Loading Data: Keep It Around
  • Saving and retrieving form data
  • Our browser can GET the form...
  • ... But it needs to POST the response
  • Setting the HTML form to send a POST request
  • Setting up a Sinatra route for a POST request
  • Converting objects to and from strings with YAML
  • Saving objects to a file with YAML::Store
  • Saving movies to a file with YAML::Store
  • A system for finding Movies in the YAML::Store
  • Numeric IDs for Movies
  • Finding the next available movie ID
  • A class to manage our YAML::Store
  • Using our MovieStore class in the Sinatra app
  • Testing the MovieStore
  • Loading all movies from the MovieStore
  • Loading all movies from the MovieStore (continued)
  • Loading all movies in the Sinatra app
  • Building HTML links to individual movies
  • Building HTML links to individual movies (continued)
  • Named parameters in Sinatra routes
  • Using a named parameter to get a movies ID
  • Defining routes in order of priority
  • Finding a Movie in the YAML::Store
  • An ERB template for an individual movie
  • Finishing the Sinatra route for individual movies
  • Lets try it all out!
  • Our complete app code
  • Your Ruby Toolbox
  • Up Next...
• A. Leftovers: The top ten topics (we didnt cover)
  • #1 Other cool libraries
    • Ruby on Rails
    • dRuby
    • CSV
  • #2 Inline if and unless
  • #3 Private methods
  • #4 Command-line arguments
  • #5 Regular expressions
  • #6 Singleton methods
  • #7 Call any method, even undefined ones
  • #7 Call any method, even undefined ones (continued)
  • #8 Automating tasks with Rake
  • #9 Bundler
  • #10 Other books
• B. This isnt goodbye
• C. Oreilly: Ruby
  • What will you learn from this book?
  • Whats so special about this book?
• Index
• About the Author
• Copyright

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