encrypt_alt.rb

def encrypt_alt(message,final_shift)
    character_set = ("a".."z").to_a << " "
    split_message = message.split("")
    offset_array = split_message.map.with_index do |char, index|
      f_index = (index % 4) + 1
      new_index = final_shift[f_index - 1]
      char_index = character_set.find_index(char)
      new_char_index = (char_index + new_index) % 27
      character_set[new_char_index]
    end.join
  end