Question

In Rails, how do you assign all attributes of an item automatically depending on the first attribute

First part of my question is at the link above,

I have grabbed a random property using the example @ring.display_name = Ring::DISPLAY_NAME.sample. That’s not a problem. What is troubling me is grabbing the rest of the attributes.

I now need to grab @ring.gold, @ring.roll and @ring.bonus in accordance to what was randomly selected for the display_name. Here is a look at my model right now, I know it’s wrong, but can you tell me if there is a better way of doing this, one that works perhaps?

class Ring < ActiveRecord::Base



  # Display_name
  DISPLAY_NAME = [ 'Beginners', 'Silver', 'Gold', 'Diamond' ]

  # Gold
  if Ring.display_name == 'Beginners'
    GOLD = [ 0 ]
  end
  if Ring.display_name == 'Silver'
    GOLD = [ 0 ]
  end
  if Ring.display_name == 'Gold'
    GOLD = [ 0 ]
  end
  if Ring.display_name == 'Diamond'
    GOLD = [ 0 ]
  end


  # Roll
  if @ring.display_name == 'Beginners'
    ROLL = [ 1 ]
  end  
  if @ring.display_name == 'Silver'
    ROLL = [ 1, 2, 3 ]
  end
  if @ring.display_name == 'Gold'
    ROLL = [ 2, 3, 4 ]
  end
  if @ring.display_name == 'Diamond'
    ROLL = [ 4, 5, 6 ]
  end

  # Bonus
  if Ring.display_name == 'Beginners'
    BONUS = [ ring.user.level + 1 ]
  end  
  if Ring.display_name == 'Silver'
    BONUS = [ ring.user.level + (1 + rand(3)) ]
  end
  if Ring.display_name == 'Gold'
    BONUS = [ ring.user.level + (1 + rand(5)) ]
  end
  if Ring.display_name == 'Diamond'
    BONUS = [ ring.user.level + (1 + rand(8)) ]
  end

  attr_accessible :description, :display_name, :roll, :bonus, :total, :image, :gold


end

As you can see by the code, I have tried using an ‘if Ring.display_name’ and also a ‘if @ring.display_name’ Neither of these worked, as I assume whoever reading this already knows they woudn’t.

Thanks!

UPDATED!

Here is the code I am currently using. This isn’t right, I don’t quite understand how to use this technique. Take a look at what I have.

class Ring < ActiveRecord::Base

  # Display_name
  DISPLAY_NAME = [ 'Silver', 'Gold', 'Diamond' ]

  # Rolls
  ROLL = {
    'Silver'    => [1, 2, 3],
    'Gold'      => [2, 3, 4],
    'Diamond'   => [4, 5, 6]
  }
  self.roll = ROLL[self.display_name]

  BUY = {
    'Silver'    => [100..180],
    'Gold'      => [140..200],
    'Diamond'   => [180..350]
  }
  self.buy = BUY[self.display_name]

  BONUS = {
    'Silver'    => [(1 + rand(3))],
    'Gold'      => [(3 + rand(5))],
    'Diamond'   => [(5 + rand(8))]
  }
  self.bonus = BONUS[self.display_name].call

  attr_accessible :user, :active, :display_name, :description, :gold, :buy, :sell, :roll, :bonus, :total, :image, :description


end

and in my controller:

def create
    @ring = Ring.new
    @ring.display_name = Ring::DISPLAY_NAME.sample

    @ring.save

    redirect_to @ring
  end

The way I understand it, if I tell it to pick a random display_name, all other fields will be filled in according to what I have in the model, is that correct?

Answer 1

You can make hashes out of your conditionals, like following:

class Ring < ActiveRecord::Base

  # Display_name
  DISPLAY_NAME = [ 'Silver', 'Gold', 'Diamond' ]

  # Rolls
  ROLL = {
    'Silver'    => [1, 2, 3],
    'Gold'      => [2, 3, 4],
    'Diamond'   => [4, 5, 6]
  }

  BUY = {
    'Silver'    => [100..180],
    'Gold'      => [140..200],
    'Diamond'   => [180..350]
  }

  BONUS = {
    'Silver'    => ->(){(1 + rand(3))},
    'Gold'      => ->(){(3 + rand(5))},
    'Diamond'   => ->(){(5 + rand(8))}
  }

  attr_accessible :user, :active, :display_name, :description, :gold, :buy, :sell, :roll, :bonus, :total, :image, :description

  def display_name=(name)
    super(name)
    self.roll = ROLL[self.display_name]
    self.buy = BUY[self.display_name]
    self.bonus = BONUS[self.display_name].call
  end
end