rails collection_select to prompt or include_blank?

Well I just wasted a bit of time but learned something in the end. When working with the rails form helper collection_select you might be interested in the difference between the prompt option and include_blank? option

include_blank will always create an option tag, prompt will only create an option tag when creating a new record - in most cases I prefer include_blank

both take either a boolean or a string, if true is passed then include_blank will create an option with no display text and prompt defaults to the display text of 'Please Select'

collection_select(:product,
  :category_id,
  Category.all,    
  :id,    
  :title,    
  {:prompt => true}
)

collection_select(:product,    
  :category_id,    
  Category.all,    
  :id,    
  :title,    
  {:include_blank => 'Please Select'}
)

both of these result in the same html, but the first one will not include the 'Please Select' option when you return to edit the previously created Product

See also

• http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html
• Select helper methods in Ruby on Rails