How to use a variable as object attribute in rails?

Question

I have a PaymentDetail model with attribute \'home_address_country\', so i can use

    @payment_detail.home_address_country //where @payment_detail is object         


        

Answer 1

• Reading AR attribute

  @payment_detail.send("#{address_type}_address_country")
  

  OR

  @payment_detail.read_attribute("#{address_type}_address_country")
  

• Writing AR attribute

  @payment_detail.send("#{address_type}_address_country=", value)
  

  OR

  @payment_detail.write_attribute("#{address_type}_address_country", value)
  

• Setting instance variable

  @payment_detail.instance_variable_set("@#{address_type}_address_country", value)
  

• Getting instance variable

  @payment_detail.instance_variable_get("@#{address_type}_address_country")
  

Reference

• send method documentation
• read_attribute method documentation
• write_attribute method documentation
• instance_variable_get method documentation
• instance_variable_set method documentation

Answer 2

Recommended way for Rails 3 is to use dictionary-like access:

attr = @payment_detail["#{address_type}_address_country"]
attr = "new value"
@payment_detail["#{address_type}_address_country"] = attr

read_attribute and write_attribute methods work for Rails 2 only.