ruby-on-rails – 如何在RoR中初始化Model对象？

这是班级：

class User < ActiveRecord::Base

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

end

在rails控制台–sandbox中,我可以更改值.但我想用某些值启动对象.

例如,我希望测量以“US”开头,bmr_formula以“Katch”开头……等等而不是nil.

现在,一切都从零开始.

我将继续展示我尝试过每次尝试得到的结果.

这是有效的：

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 >

感谢大家的帮助！

全班：

attr_accessible :name,:protien_factor


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

安慰：

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

课程底部：

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

安慰：

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

课程底部：

self.@measurement = "US"

安慰：

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

类：

after_initialize :measurement,:protien_factor

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

安慰：

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