Ruby 101

steps on learning Ruby for Rails

Getting Started

Install rbenv: https://github.com/rbenv/rbenv

Index

Introduction

$ ruby --version
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]

$ ruby
puts "Hello World"
^D
Hello World

$ irb
irb(main):001> puts "Hello World"
Hello World
=> nil
irb(main):002* def sum3(x, y, z)
irb(main):003*   x + y + z
irb(main):004> end
=> :sum3
irb(main):005> sum3(1, 2, 3)
=> 6

Basic Syntax

$ ruby myprog.rb
Hello, World!
It is 2024-09-11 13:10:05 +0700

$ chmod +x shebang.rb
$ ./shebang.rb
Hello, World!
It is 2024-09-11 13:15:16 +0700

Ruby is a pure object-oriented language with no basic types.

$ ruby puts_example.rb
9
2
true
I'm playing gin joint

$ ruby hello.rb
Hello, Rick, and Goodbye!
Hello, Lori, and Goodbye!

Practice time, write a ruby code which will give output like this:

$ ruby practice.rb
Hello World!
Good morning! Mac

Array, Hash and Symbol

$ ruby array.rb
the first element is 1
the array is now [1, "cat", nil]

$ ruby hash.rb
woodwind
string

0
1

$ ruby symbol.rb
hello
hello
Symbol
You are going north
You are going south

$ ruby hash_with_symbol_keys.rb
woodwind
string

woodwind
string

Control Structure

$ ruby if.rb
Go to work

$ ruby while.rb
1
2
3
4
5
1
2
3

$ ruby statement_modifier.rb
Danger, Will Robinson
Danger, Will Robinson
16
256
65536
65536

Blocks

$ ruby basics.rb
hello
hello
hello
hello
hello
hello
hi there
Start of method
In the block
In the block
End of method

$ ruby block_with_arguments.rb
Dave says hello
Andy says goodbye

Classes and Objects

$ ruby person.rb
Hello, my name is Alice and I am 30 years old.
Hello, my name is Bob and I am 25 years old.
It's my birthday! I am now 31 years old.
I've changed my name to Robert.

Methods

$ ruby method.rb

$ ruby method2.rb

$ ruby parameter.rb

$ ruby variable_length.rb

$ ruby hash_params.rb

$ ruby block.rb

$ ruby passing_block_arguments.rb