检查elixir中字符串的第一个和最后一个字符之间的字符

def check_characters_between_first_and_last(str) do
  first_char = String.slice(str, 0)
  last_char = String.slice(str, -1)
  
  if String.length(str) > 2 do
    characters_between = String.slice(str, 1, -2)
    IO.puts "Characters between first and last: #{characters_between}"
  else
    IO.puts "No characters between first and last"
  end
end

check_characters_between_first_and_last("Hello")  # Output: No characters between first and last
check_characters_between_first_and_last("Elixir")  # Output: Characters between first and last: li