array_to_hash.rb

# method 1
hash = [[:first_name, 'Shane'], [:last_name, 'Harvie']].inject({}) do |result, element|
  result[element.first] = element.last
  result
end

hash # => {:first_name=>"Shane", :last_name=>"Harvie"}

# method 2

Hash[*[[:first_name, 'Shane'], [:last_name, 'Harvie']].flatten] # => {:first_name=>"Shane", :last_name=>"Harvie"}