Validation of Array in rails 4

Question

How can I apply validation on array elements so that it can raise an error that it can not be blank ??

    validates :my_arr , presence: true

It will check [" "].present? which will return true.But I need to check its element my_arr.last.

I have implemented following one in my model:

 if self.dma_area.last.blank?
   errors.add(:dma_area, "should be selected")
 end

I have tried it with lot of other option like (allow_blank: false exclusion etc) and I found above one is working but I am in doubt whether it is in rails standards.

Is above solution is fine according to rails standards/conventions.??

Waiting for good working solution.

Ivan Denysov · Accepted Answer · 2014-01-16 20:33:21Z

2

validates :presence_of_last_element
...

private
... 
def presence_of_last_element
  unless my_arr.last.present?
    errors.add(:my_arr, "should not contain empty elements") 
end

edited Jan 16, 2014 at 20:33

answered Jan 16, 2014 at 20:28

Ivan Denysov

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Comments

Manoj Sehrawat · Accepted Answer · 2014-01-17 01:32:11Z

1

What you can do is use before_validation call back and reject all invalid values from your array. With that your normal validation should work fine.

You can try it like:

validates :my_arr , presence: true

before_validation :reject_invalid_values_from_my_arr
...

=====================
= Protected methods =
=====================
protected
  def reject_invalid_values_from_my_arr  
    self.my_arr = my_arr.compact.reject{|value| value.blank?}
  end
...

answered Jan 17, 2014 at 1:32

Manoj Sehrawat

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