如何枚举地图以生成结构列表

Question

我是 Elxir 的新手。

如果我有以下地图

recos = %{"itemScores" => [%{"item" => "i0", "score" => 0.0126078259487225},
%{"item" => "i3", "score" => 0.007569829148848128},
%{"item" => "i4", "score" => 0.007023984270125072},
%{"item" => "i33", "score" => 0.0068045477730524495}]}

（这是地图吧？）

我将如何枚举所有 itemScores 以生成 RecommendationItems 列表？

defmodule RecommendedItem do
  defstruct [:item, :score]
end 

我想它会以某种方式为 Enum.map(recos["itemScores"], fn->) 开具发票，但我不确定。

Answer 1

这段代码应该做你想要的：

defmodule RecommendedItem do
  defstruct item: "", score: 0
end

defmodule Demo do

  defp parse_list([]), do: []

  defp parse_list([%{"item" => i, "score" => s} | tail]) do
    [%RecommendedItem{item: i, score: s} | parse_list(tail) ]
  end

  def create_recommend_list(%{"itemScores" => score_list})  do
    parse_list(score_list)
  end

end

# And this is how you'd call it.

recos = %{"itemScores" => [%{"item" => "i0", "score" => 0.0126078259487225},
%{"item" => "i3", "score" => 0.007569829148848128},
%{"item" => "i4", "score" => 0.007023984270125072},
%{"item" => "i33", "score" => 0.0068045477730524495}]}

l = Demo.create_recommend_list(recos)

# l = [%RecommendedItem{item: "i0", score: 0.0126078259487225},
# %RecommendedItem{item: "i3", score: 0.007569829148848128},
# %RecommendedItem{item: "i4", score: 0.007023984270125072},
# %RecommendedItem{item: "i33", score: 0.0068045477730524495}]

我希望这有帮助。虽然我想我明白你在问什么，但我不认为将每个映射转换为结构确实是你想要做的。