array_methods_refactoring.rb

# The code that follows is a Dog class with a multitude of class methods
# that filter and transform Dog.all for various purposes. Unfortunately,
# the author of these methods used .each to accomplish the iteration in 
# all cases, when .map (or .collect), .find, or .select would have been
# a better choice. Read the code, run it with some test data (create a 
# runner file!) and understand what the methods are doing. Refactor to 
# use a different array method.

class Dog

  attr_reader :name, :age, :likes

  @@all = []

  def initialize(name, age, likes = []) 
    @name = name
    @age = age
    @likes = likes
    @@all << self
  end

  def self.all
    @@all
  end

  def self.named(name)
    self.all.each do |hound|
      if hound.name == name
        return hound
      end
    end
    nil
  end

  def self.all_names
    names = []
    self.all.each do |doggie|
      names << doggie.name
    end
    names
  end

  def self.senior_dogs
    senior_dogs = []
    self.all.each do |doggo|
      if doggo.age > 10
        senior_dogs << doggo
      end
    end
    senior_dogs
  end

  def self.puppies
    puppies = []
    self.all.each do |pup|
      if pup.age < 2
        puppies << pup
      end
    end
    puppies
  end

  def self.all_ages_in_human_years
    ages_in_human_years = []
    self.all.each do |pupper|
      ages_in_human_years << pupper.age * 7
    end
    ages_in_human_years
  end

  def self.all_who_like(like)
    dogs_who_like_the_thing = []
    self.all.each do |doge|
      if doge.likes.include?(like)
        dogs_who_like_the_thing << doge
      end
    end
    dogs_who_like_the_thing
  end

end