Hash transform composing functions

hash_transform.rb

# setup data
data1 =  {1 => %W{ A B C D E} , 2 => %W{ A B C D E }, 3 => %W{ A B C D E }, 4 => %W{ A B C D E } }
list = data1[1]

def swap_list_values_to_keys(key, list)
  list.reduce({}) { |a, value|  a.merge({key => value.downcase}.invert)  }  
end

# p swap_list_values_to_keys(1, list)
# => {"a"=>1, "b"=>1, "c"=>1, "d"=>1, "e"=>1}

# builds the new array by reducing over the previous method.
def transform(hash)
  hash.each_pair.reduce([]) do |a, pair|
    key  = pair.first
    list = pair.last
    a << (swap_list_values_to_keys(key, list))
  end
end

# p transform(data1)
# => [{"a"=>1, "b"=>1, "c"=>1, "d"=>1, "e"=>1}, {"a"=>2, "b"=>2, "c"=>2, "d"=>2, "e"=>2}, {"a"=>3, "b"=>3, "c"=>3, "d"=>3, "e"=>3}, {"a"=>4, "b"=>4, "c"=>4, "d"=>4, "e"=>4}]