Elixir 練習問題 StringsAndBinaries-7

defmodule Sales do
  def csv_to_list(filename) do
    {:ok, file} = File.open(filename, [:read])
    headers = (IO.read(file, :line) |> parse_csv_atom)
    IO.stream(file, :line)
    |> Enum.map(fn l -> parse_csv(l) end)
    |> Enum.map(fn sales -> Enum.zip(headers, sales) end)
  end

  defp parse_csv_atom(line) do
    String.trim(line, "\n")
    |> String.split(",")
    |> Enum.map(&String.to_atom/1)
  end

  defp parse_csv(line) do
    [id, ship_to, net_amount] = (String.trim(line, "\n") |> String.split(","))
    [String.to_integer(id), String.to_atom(String.trim(ship_to, ":")), String.to_float(net_amount)]
  end
end

IO.inspect Sales.csv_to_list("sales.csv")

^o^ > cat sales.csv
id,ship_to,net_amount
123,:NC,100.00
124,:OK,35.50
125,:TX,24.00
126,:TX,44.80
127,:NC,25.00
128,:MA,10.00
129,:CA,102.00
130,:NC,50.00

^o^ > elixir practice_11_7.exs
[[id: 123, ship_to: :NC, net_amount: 100.0],
 [id: 124, ship_to: :OK, net_amount: 35.5],
 [id: 125, ship_to: :TX, net_amount: 24.0],
 [id: 126, ship_to: :TX, net_amount: 44.8],
 [id: 127, ship_to: :NC, net_amount: 25.0],
 [id: 128, ship_to: :MA, net_amount: 10.0],
 [id: 129, ship_to: :CA, net_amount: 102.0],
 [id: 130, ship_to: :NC, net_amount: 50.0]]