hash.rb

  def index
    @carriers = Carrier.all.sort_by(&:name)
    @lines = Array.new
    @carriers.each do |c|
      c.sw_profiles.each do |p|
        @lines.push(prepend_hash_keys("carrier", c.attributes).merge(prepend_hash_keys("sw_profile", p.attributes)))
      end
    end
  end

  def prepend_hash_keys(name, hash)
    h = {}
    hash.each do |k, v|
      h["#{name}_#{k}"] = v
    end
    h
  end

# which results in 
[{Carrier id: ... name: ...} => {SWProfile id: ... name: ...}...]

# what I need is a new Array:

[{NewHash carrier_id: ... carrier_name: ... sw_profile_name: ... ...}, {} ...]