Start with Ruby

Introduction

Ruby is an open source programming language with a focus on simplicity and productivity.

Here are some main features of Ruby :

Ruby is open-source and is freely available on the Web, but it is subject to a license
Ruby is a server-side scripting language similar to Python and PERL
Ruby is very much scalable
Big programs written in Ruby are easily maintainable
Ruby can be used for developing Internet and intranet applications
Ruby can be embedded into Hypertext Markup Language (HTML)

You'll find here some examples of using Ruby for my personnal use and test.

Hope it can help :)

Summary

Tools and version
Folder structure
Test files :
Useful resources :
- Reserved word
- Keywords and methods
Sources

Tools and versions

OS
- Kali Linux OS - Ruby v3.1.2
- Windows OS - Ruby v3.2.2
IDE
- VSCodium v1.77.1

Folder structure

├── Makefile
├── README.md
└── src
   ├── examples
   |  ├── example_1.rb
   |  ├── example_2.rb
   |  ├── example_3.rb
   |  ├── example_4.rb
   |  ├── example_5.rb
   |  ├── example_6.rb
   |  ├── example_7.rb
   |  ├── example_8.rb
   |  └── example_9.rb
   |  ├── example_10.rb
   |  ├── example_11.rb
   |  ├── example_12.rb
   |  ├── example_13.rb
   |  ├── example_14.rb
   ├── ask-question.rb
   ├── tips.rb
   └── tuto.rb

Test files

Requirements and Makefile usage

Considering you already have Ruby on your host machine, you can use make to read any file inside this repo

make run FILE=[name of file]

Simple tuto

tuto.rb is a simple ruby tutorial

Ask a question

ask-question.rb use the method gets and chomp

When you enter your word, you'll see that your sentence is broken down into two lines and chomp can remove "\n" from the answer.

Examples

Launch an example :

make run_example FILE=example_1

example_1: convert the answer from string to number and test if the number is even, conditions
example_2: Guess the number, comparison
example_3: Is the word a palindrom ?
example_4: array
example_5: Hash and Hash class
example_6: Symbols
example_7: Loop, guess again the number WHILE loop
example_8: Loop, guess again the number FOR loop, each for arrays and hash
example_9: Loop, iterator LOOP BREAK
example_10: Frequency of a word
example_11: Methods
example_12: Block & proc
example_13: Deep dive into proc
example_14: Lambda

Tips

Antoher way to create an array of string

%w{apple pear fig} => ["apple", "pear", "fig"] # shortcut

respond_to?(:method_name) => let you check if the value given can be used for the method, give a boolean value
convert array of mixed number int and string into array of integer:

array = [1, "2", 3, "4", 5]
puts array.inspect

# Solution 1
array_1 = array.map { |i| i.to_i }
puts array_1.inspect

# Solution 2
array_2 = array.map(&:to_i)
puts array_2.inspect

Useful Resources

Reserved Words

The following list shows the reserved words in Ruby. These words may not be used as constant or variable names.

Keywords and methods

Single line comment:

# This is a comment

Block comment

=begin
This is a comment
And another line
And another comment
=end

Create method

def method_name
    code
end

#with parameters
def method_name(params)
    code
end

Variables

varname = "Hello"

Conditions

&& # AND
|| # OR
! # reverse everything after

Conventions

method? # the ? gives a boolean
varname! # the ! indicate that value is modified

Convert

to_i # convert to integer
to_s # convert to string

Insert value

# same result
"Hello" + "World" => "Hello" << "World"

Block

def demo_1
  puts "Hello"
  yield # add the block "How are you?"
  puts "Bye bye"
end

demo_1 { puts "How are you?" } # you have to add a block with yield keyword

Error in case you didn't add block:

Proc

proc_name = Proc.new { ...code }

method_name(other_params, &proc_name)

# the & is for casting the new proc into block

proc_name.call(give_args) # reuse proc registered

lambda { } # a special proc and wait for a specific number of argument

# turn the block into proc
def method_name(params, &proc_name)
  ...code
  proc_name.call(give_args)
end

method_name(args) {...block_turn_into_proc}

helene-nguyen / ruby-starter