Question

I have a hash that looks like this:

extras = {'facebook' => '', 'twitter' => ''}

And my User attributes are like this:

class User < ActiveRecord::Base
  attr_accessible :facebook, :twitter, #...

I would like to retrieve the data defined in my extras hash in the following fashion (or a better oen – that is the one that came up to my mind)

extras.each do |k,v|
    extras[k] = @user.k
end

Is this even possible ?

Answer 1

Yes, you can do that with the .send(:method) or the .try(:method):

# with this kind of hash:
extras = {'facebook' => '', 'twitter' => ''}

You can do that to gather the user’s info:

extras.each_key do |key|
  extras[key] = @user.send(key.to_sym)      
end

Or with .try(), which is safer: it will not raise an NoMethodError in case of unknown key sent to user:

extras.each_key do |key|
  extras[key] = @user.try(key.to_sym)
end

You can do it with a map also:

extras.each_key{ |k| extras[k] = @user.send(k.to_sym) }

I made a post about this code, you can see it here:
http://rails.co.nf/?p=31