You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
Ruby Programming Language – Source Code Repository
Learn Elegant Programming, Web Development with Ruby, Automation, and Building Real Applications from Scratch
This repository contains every code example from the book, organized by chapter. Each folder maps directly to a chapter so you can find any example in seconds without searching through the text.
How to Use This Repository
Clone the repository to your local machine:
git clone https://github.com/ey11gen/ruby-programming-codes.git
cd ruby-programming-codes
Make sure Ruby is installed. All examples require Ruby 3.0 or later. Run the following command to check:
ruby --version
Navigate to any chapter folder and run a file:
cd chapter_01
ruby 01_hello_world.rb
For Chapter 17 (RSpec tests), install RSpec first:
gem install rspec
rspec calculator_spec.rb
For Chapter 20 (RubyTask application), run from inside the rubytask directory:
cd chapter_20/rubytask
ruby rubytask.rb help
ruby rubytask.rb add "My first task" --priority high
ruby rubytask.rb list
Repository Structure
ruby-programming-codes/
├── chapter_01/ Getting Started with Ruby
├── chapter_02/ Variables, Data Types, and Operators
├── chapter_03/ Strings and Text Processing
├── chapter_04/ Control Flow and Decision Making
├── chapter_05/ Loops, Iterators, and Blocks
├── chapter_06/ Arrays and Hashes
├── chapter_07/ Methods and Program Structure
├── chapter_08/ OOP: Classes and Objects
├── chapter_09/ OOP: Inheritance and Polymorphism
├── chapter_10/ Modules, Mixins, and Code Organization
├── chapter_11/ Error Handling and Exceptions
├── chapter_12/ File I/O and the File System
├── chapter_13/ The Ruby Standard Library
├── chapter_14/ RubyGems, Bundler, and Dependencies
├── chapter_15/ Functional Programming Patterns
├── chapter_16/ Metaprogramming in Ruby
├── chapter_17/ Testing with RSpec and Minitest
├── chapter_18/ Web Development with Ruby on Rails
├── chapter_19/ Automation and Scripting
└── chapter_20/ Building a Complete Ruby Application
└── rubytask/ ← Fully runnable CLI task manager
Chapter-by-Chapter File Guide
Chapter 01 – Getting Started with Ruby
File
Description
01_hello_world.rb
Your first Ruby program using puts
02_output_methods.rb
Difference between puts, print, and p
03_irb_arithmetic.rb
Arithmetic expressions for IRB exploration
04_sequence_demo.rb
How Ruby executes code line by line
05_error_demo.rb
Understanding Ruby error messages
06_comments_demo.rb
Single-line and multi-line comments
Chapter 02 – Variables, Data Types, and Operators
File
Description
01_variables.rb
Assignment, snake_case naming, compound operators
02_numbers.rb
Integers, floats, arithmetic, number methods
03_booleans_nil_symbols.rb
Booleans, nil, and symbols explained
04_operators.rb
Arithmetic, comparison, and logical operators
05_type_conversion.rb
to_i, to_f, to_s and edge cases
06_user_input.rb
gets.chomp for reading from the terminal
Chapter 03 – Strings and Text Processing
File
Description
01_string_literals.rb
Single quotes, double quotes, heredocs, freeze
02_string_interpolation.rb
Embedding expressions inside strings
03_string_methods.rb
upcase, strip, include?, gsub, split, join, center
04_regular_expressions.rb
Patterns, match?, gsub with regex, capture groups
Chapter 04 – Control Flow and Decision Making
File
Description
01_truthiness.rb
Only false and nil are falsy in Ruby
02_if_statements.rb
if, elsif, else, unless, return values
03_case_statement.rb
case/when with values and ranges
04_inline_ternary.rb
One-line if/unless and the ternary operator
05_combining_conditions.rb
&&, `
Chapter 05 – Loops, Iterators, and Blocks
File
Description
01_while_until_loop.rb
while, until, loop, break, next
02_times_upto_downto.rb
Counted iteration with block parameters
03_each_map_select_reject.rb
Collection iterators with blocks
04_reduce_chaining.rb
reduce/inject and chained pipelines
05_blocks_procs_lambdas.rb
yield, Proc.new, lambda syntax
Chapter 06 – Arrays and Hashes
File
Description
01_arrays_basics.rb
Creating arrays, indexes, slice, first, last
02_array_methods.rb
push/pop/shift/unshift, sort, uniq, flatten
03_hashes.rb
Hash creation, access, update, delete, iterate
04_nested_structures.rb
Arrays of hashes, hashes of hashes
05_ranges.rb
Inclusive/exclusive ranges, step, iteration
Chapter 07 – Methods and Program Structure
File
Description
01_methods_basics.rb
Defining methods, implicit/explicit return
02_parameters.rb
Required, optional, keyword, splat parameters
03_predicate_bang_alias.rb
? and ! conventions, alias keyword
04_scope.rb
Variable scope boundaries around methods
05_multi_method_program.rb
Receipt generator: single-responsibility design
Chapter 08 – OOP: Classes and Objects
File
Description
01_classes_objects.rb
Defining classes, creating instances with .new
02_initialize_instance_vars.rb
Constructor and @ instance variables
03_accessors.rb
attr_reader, attr_writer, attr_accessor
04_instance_methods_self_to_s.rb
self, to_s, method chaining with scale!
05_class_methods.rb
self.method_name factory pattern
06_visibility_public_private.rb
public/private with BankAccount
Chapter 09 – OOP: Inheritance and Polymorphism
File
Description
01_inheritance.rb
< operator, inherited methods, is_a?
02_method_override_super.rb
Overriding methods, calling super
03_polymorphism_duck_typing.rb
Duck typing: speak on Dog, Cat, Parrot, Robot
04_shapes_polymorphism.rb
Shape hierarchy with NotImplementedError
05_comparable_module.rb
include Comparable and the <=> operator
Chapter 10 – Modules, Mixins, and Code Organization
File
Description
01_modules_mixins.rb
include for sharing behavior across classes
02_enumerable_module.rb
Custom Library class with full Enumerable
03_namespaces.rb
module Geometry with :: namespace operator
04_extend_prepend.rb
extend for class methods, prepend for wrapping
05_require_example.rb
require/require_relative, nested namespaces
Chapter 11 – Error Handling and Exceptions
File
Description
01_exception_hierarchy.rb
Exploring the exception ancestor chain
02_begin_rescue.rb
Catching exceptions with multiple rescue clauses
03_ensure_else.rb
Guaranteed cleanup with ensure, success with else
04_raising_exceptions.rb
raise, guard clauses, re-raising with bare raise
05_custom_exceptions.rb
Full custom exception hierarchy for a payment system
06_retry.rb
Resilient retry loop with counter and sleep
Chapter 12 – File I/O and the File System
File
Description
01_reading_files.rb
File.read, foreach, File.open block pattern
02_writing_files.rb
Writing with "w", appending with "a", File.write
03_filesystem.rb
File.exist?, Dir.glob, mkdir, chdir
04_csv_processing.rb
Reading and writing CSV with headers
05_json_files.rb
JSON.generate, JSON.pretty_generate, JSON.parse
Chapter 13 – The Ruby Standard Library
File
Description
01_date_time.rb
Time.now, Date.today, strftime, date arithmetic
02_math_securerandom.rb
Math module, SecureRandom for tokens and UUIDs
03_benchmark.rb
Comparing implementations with Benchmark.bm
04_set_struct.rb
Set for unique collections, Struct for data objects
05_network_requests.rb
open-uri GET and Net::HTTP POST requests
Chapter 14 – RubyGems, Bundler, and Dependencies
File
Description
01_gem_usage.rb
Using the colorize gem after gem install colorize
Gemfile
Example Gemfile with version constraints and groups
my_utility_gem/
Complete gem skeleton with gemspec and lib structure
Chapter 15 – Functional Programming Patterns
File
Description
01_pure_methods.rb
Writing side-effect-free pure methods
02_immutability.rb
freeze, immutable-style programming
03_method_chaining.rb
Transformation pipelines with group_by
04_query_builder.rb
Chainable DSL returning self
05_lazy_evaluation.rb
lazy, infinite ranges, custom Enumerator
06_function_composition.rb
& prefix with Procs, >> composition operator
Chapter 16 – Metaprogramming in Ruby
File
Description
01_open_classes.rb
Adding prime?, factorial, titleize to built-ins
02_reflection.rb
respond_to?, instance_variables, public_methods
03_method_missing.rb
FlexibleRecord with dynamic attributes
04_define_method.rb
Generating 15 methods with a loop and define_method
05_html_builder_dsl.rb
Full HTML DSL using instance_eval and blocks
Chapter 17 – Testing with RSpec and Minitest
File
Description
calculator.rb
The Calculator class under test
test_calculator.rb
Full Minitest suite (ruby test_calculator.rb)
calculator_spec.rb
Full RSpec specification (rspec calculator_spec.rb)
test_with_mocks.rb
Dependency injection and Minitest::Mock
Chapter 18 – Web Development with Ruby on Rails
File
Description
config/routes.rb
resources :tasks and root route
app/controllers/tasks_controller.rb
All 7 RESTful actions with before_action
app/models/task.rb
Validations, scopes, complete! method
db/migrate/..._create_tasks.rb
Database migration with all column types
app/views/tasks/index.html.erb
ERB list view with link helpers
app/views/tasks/_form.html.erb
Form partial with error display
Note: Rails files require a full Rails application to run. Generate one with rails new taskmanager and copy these files into the appropriate directories.
Chapter 19 – Automation and Scripting with Ruby
File
Description
01_option_parser_tool.rb
CLI tool with flags, help text, and exit codes
02_file_organizer.rb
Sorts files by extension with dry-run mode
03_web_scraping.rb
Nokogiri CSS selectors and attribute access
04_external_commands.rb
system, %x(), $?, Open3
05_log_monitor.rb
Log parser with grouping and analysis report
Chapter 20 – Building a Complete Ruby Application
The complete RubyTask CLI application lives in chapter_20/rubytask/.
File
Description
rubytask.rb
Entry point with shebang
lib/task.rb
Task domain model with validation and serialization
Ruby programming examples, scripts, and exercises from the Ruby Programming book, organized by chapters to help readers learn and practice efficiently.