I am unable to assign a value to a virtual attribute in the after_initialize method:
attr_accessor :hello_world
def after_initialize
self[:hello_world] = "hello world"
end
In my view file:
hello world defaulted? <%= @mymodel.hello_world %>
This doesn't return any output.
Do you have any suggestions or any alternative to set up a default value for a virtual attribute?
You are using an odd method of assignation within your after_initialize callback. You just need to assign to self.hello_world or even @hello_world. Your assignment has created a hash within your instance of the class with a key of :hello_world and the value as expected. Within your view you could reference @mymodel[:hello_world] but this is far from idiomatic.
The following example model and console session shows the effect of using various methods of initializing the virtual attribute.
class Blog < ActiveRecord::Base
attr_accessor :hello_world1, :hello_world2, :hello_world3
def after_initialize
self.hello_world1 = "Hello World 1"
self[:hello_world2] = "Hello World 2"
@hello_world3 = "Hello World 3"
end
end
ruby-1.9.2-p0 > b=Blog.new
=> #<Blog id: nil, title: nil, content: nil, created_at: nil, updated_at: nil>
ruby-1.9.2-p0 > b.hello_world1
=> "Hello World 1"
ruby-1.9.2-p0 > b.hello_world3
=> "Hello World 3"
ruby-1.9.2-p0 > b.hello_world2
=> nil
ruby-1.9.2-p0 > b[:hello_world2]
=> "Hello World 2"
ruby-1.9.2-p0 > b[:hello_world1]
=> nil
