Build hash from collection of ActiveRecord Models

Question

I'm trying to build a hash from a Model.

This is the type of hash I want to build.

{"United Sates" => "us", "United Kingdom" => "uk" .....} 

I have tried so many ways now I'm just going around in circles.

Here are just some of my poor attempts.

select = Array.new countries.each do |country|   # select.push({country.name => country.code })   # select[country.name][country.code] end  h = {}  countries.each do |c|   # h[] = {c.name => c.code}   # h[] ||= {}    # h[][:name] = c.name   # h[][:code] = c.code    #h[r.grouping_id][:name] = r.name   # h[r.grouping_id][:description] = r.description end 

Please can some advise.

Thank You

Answer 1

Here are some one-liner alternatives:

# Ruby 2.1+ name_to_code = countries.map{ |c| [c.name,c.code] }.to_h  # Ruby 1.8.7+ name_to_code = Hash[ countries.map{ |c| [c.name,c.code] } ]  # Ruby 1.8.6+ name_to_code = Hash[ *countries.map{ |c| [c.name,c.code] }.flatten ]  # Ruby 1.9+ name_to_code = {}.tap{ |h| countries.each{ |c| h[c.name] = c.code } }  # Ruby 1.9+ name_to_code = countries.to_a.each_with_object({}){ |c,h| h[c.name] = c.code } 

Courtesy of @Addicted's comment below:

# Ruby 1.8+ name_to_code = countries.inject({}){ |r,c| r.merge c.name=>c.code }