Ruby examples

exs.rb

Array.new(10) { rand 300 } #=> [217, 232, 274, 141, 157, 180, 11, 193, 66, 187] 
[].methods.grep /^re.*/ # => array of matched methods

# All to boolean
!!(4) # => true 
!!(nil) # false

# Different ways to call a lambda
my_lambda = -> { puts 'Hello' }
 
my_lambda.call
my_lambda[]
my_lambda.()
my_lambda.===

# Extend class with method
module Rev
  def rev
    self.reverse
  end
end

s = "abc123"
s.extend(Rev) # => :rev
s.rev # => "321cba"

# INCLUDE AND EXTEND THE RAILS PLUGIN WAY
module ActsAsCounter
  # class method
  def acts_as_lifeform
    include InstanceMethods
  end
 
  module InstanceMethods
    def count
      counter++
      save
    end
  end
end
 
ActiveRecord::Base.extend ActsAsCounter