How do I initialize an Model object in RoR?

Question

I'm creating a website where I want every user to start off with certain values for their attributes.

Here is the class:

class User < ActiveRecord::Base

  attr_accessible :name, 
              :email, 
              :goal, 
              :measurement, 
              :bmr_formula, 
              :fat_factor, 
              :protien_factor

end

In rails console --sandbox I'm able to change the values. But I want to start the object off with certain values.

For example, I want measurement to begin with "US", bmr_formula to begin with "Katch"...etc instead of nil.

right now, everything starts with nil.

I'll proceed to show what I've tried with the results each attempt got.

---

---

Here is what worked:

after_initialize do 
   self[:measurement] = "US" 
   self[:bmr_formula] = "katch"
   self[:fat_factor] = 0.655
   self[:protein_factor] = 1.25
   puts "User has been initialized!"
end


1.9.3p125 :001 > user = User.new
User has been initialized!
=> #<User id: nil, name: nil, email: nil, goal: nil, measurement: "US", bmr_formula: 
"katch", fat_factor: 0, protein_factor: 0, created_at: nil, updated_at: nil> 
1.9.3p125 :002 > 

Thanks for the help everyone!

---

---

Full Class:

attr_accessible :name, 
              :email, 
              :goal, 
              :measurement, 
              :bmr_formula, 
              :fat_factor, 
              :protien_factor


def initialize(measurement)                
@measurement = measurement
# bmr_formula = "katch"
# fat_factor = 0.655
# protien_factor = 1.25
  end

Console:

1.9.3p125 :001 > user = User.new("US")
 => #<User not initialized>

---

Bottom of Class:

 def initialize               
    @measurement = "US"
    # bmr_formula = "katch"
    # fat_factor = 0.655
    # protien_factor = 1.25
  end

Console:

1.9.3p125 :001 > user = User.new
 => #<User not initialized> 
1.9.3p125 :002 > 

---

Bottom of Class:

self.@measurement = "US"

Console:

SyntaxError: /Users/Nick/Code/Rails/fitness_app/app/models/user.rb:10: syntax error, unexpected tIVAR
self.@measurement = "US"

---

Class:

after_initialize :measurement, 
                 :bmr_formula, 
                 :fat_factor, 
                 :protien_factor

 def defaults
   self.measurement = "US"
   self.bmr_formula = "katch"
   self.fat_factor = 0.655
   self.protien_factor = 1.25
  end

Console:

1.9.3p125 :001 > user = User.new
 => #<User id: nil, name: nil, email: nil, goal: nil, measurement: nil, bmr_formula:    
nil, fat_factor: nil, protien_factor: nil, created_at: nil, updated_at: nil> 
1.9.3p125 :002 > user.measurement
=> nil 
1.9.3p125 :003 > user.bmr_formula
=> nil 

Answer 1

I would use the after_initialize callback:

after_initialize :default_values
def default_values
  self.status ||= 'P'
  self.measurement = "US"
  self.bmr_formula = "katch"
  self.fat_factor = 0.655
  self.protien_factor = 1.25
end