循環和在軌鑄造問題

Question

我在User模型得到了下面的方法

def get_employees 
    @employees = [] 
     groups.each do |i| 
     @employees << Group.find(i).employees 
     end 
     @employees 
    end 

這是控制檯打印時我把這種方法：

> >> User.find(4).get_employees 
> => [[#<Employee id: 4, first_name: "test", last_name: "test1", 
> email_address: "test@gmail.com", 
> created_at: "2010-08-25 04:23:02", 
> updated_at: "2010-08-25 04:23:02">, 
> #<Employee id: 5, first_name: "hello", last_name: "hello1", email_address: 
> "hello@gmail.com", created_at: 
> "2010-08-25 04:51:37", updated_at: 
> "2010-08-25 04:51:37">]] 

但是，下面的代碼做不工作：

>> @user.get_employees.each{|i| p i.first_name} 
NoMethodError: undefined method `first_name' for #<Class:0x9e372f0> 

我需要做什麼才能得到來自循環的employees的？

Answer 1

的Group.find(i).employees調用返回一個數組，所以你get_employees方法正在返回的數組的數組。用@employees.flatten!代替get_employees的最後一行應該有效。

Answer 2

在我看來，變量我仍然是一個數組。您將@employee聲明爲空數組，然後插入另一個由Group.find（i）.employees返回的數組。

I [0]應該包含：

#<Employee id: 4, first_name: "test", last_name: "test1", 
> email_address: "test@gmail.com", 
> created_at: "2010-08-25 04:23:02", 
> updated_at: "2010-08-25 04:23:02">, 
> #<Employee id: 5, first_name: "hello", last_name: "hello1", email_address: 
> "hello@gmail.com", created_at: 
> "2010-08-25 04:51:37", updated_at: 
> "2010-08-25 04:51:37"> 

Answer 3

正如前面的海報所說，你已經有了一個數組。爲什麼重新創建一些已經內置在rails中的邏輯？我會做這樣的事情在用戶模式：

class User < ActiveRecord::Base 
    has_many :groups 
    has_many :employees, :through => :groups 
end 

然後，你可以做User.employees