Ruby Training

Introduction

This is to summarised what I learn on the ruby Training

Returning if true

Quite liked this. On do the return if true

  def remaining_minutes_in_oven(actual_minutes_in_oven)
    return EXPECTED_MINUTES_IN_OVEN - actual_minutes_in_oven if actual_minutes_in_oven < EXPECTED_MINUTES_IN_OVEN
    raise 'Please implement the Lasagna#remaining_minutes_in_oven method'
  end

Symbols

Symbols are just an identifier

class User
  STATES = [:active, :inactive, :banned]
...

Provide you pass the same thing, they are the same thing e.g.

User.new(:active)

Predicate Method

So in ruby you have a predicate method of a method that returns true or false which is, by convention, not enforced, a method with a ?. The example below returns true if status equal true.

class User
  STATES = [:active, :inactive, :banned]

  def initialize(status)
    raise "Invalid state" unless STATES.include?(status)
    @status = status
  end

  def active?
    @status == :active
  end
end

This became a bit more obvious the usage with the example with ranges

module Chess
  RANKS = 1..8
  FILES = 'A'..'H'

  def self.valid_square?(rank, file)
    RANKS.include?(rank) && FILES.include?(file)
  end
end

Interpolation

This is how to interpolation works

my_var1 = "HELLO"
my_var2 = "FRED WAS HERE #{my_var1}"
puts my_var2