On Mon, Jan 30, 2012 at 9:09 PM, Rodrigo Ruiz <[email protected]>wrote:
> Hi, I'd like to know why I can't, or how can I, access attributes like
> that:
>
> class User < ActiveRecord::Base
> def name
> @first_name + @last_name
> end
> end
>
> first_name and last_name are user attributes in the database.
>
ActiveRecord dynamically defines "accessor methods" on the
user instance.
That user instance is accessible as 'self' inside the user instance,
so you could do
class User < ActiveRecord::Base
def name
self.first_name + self.last_name
end
end
But, in Ruby, when using a _read_ accessor, you could also write it
without the explicit 'self'.
class User < ActiveRecord::Base
def name
first_name + last_name
# same as self.first_name + self.last_name
# if there is no first_name, last_name local variable
# defined in the scope
end
end
For _write_ accessors, you _must_ put the self in front, that is:
self.full_name = "#{first_name} #{last_name}"
And the @first_name you asked about, that is an "instance variable".
Read one of the many Ruby tutorials or books to understand this better.
HTH,
Peter
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