elixir - 在 Elixir 中组契约(Contract)一个键上的两个 map

Question

我对 Elixir 很陌生，只是想找到将两张 map 与同一个键组合在一起的最佳方法。更具体:

name_map = %{
  105 => "Jim",
  48 => "Maria",
  62 => "Karen",
  888 => "Foo"
}

job_map = %{
  105 => "Social worker",
  48 => "Programmer",
  62 => "Teacher",
  999 => "Bar"
}

我想得到

combined_map = %{
  105 => %{"name" => "Jim", "job" => "Social worker"},
  48 => %{"name" => "Maria", "job" => "Programmer"},
  62 => %{"name" => "Karen", "job" => "Teacher"},
  888 => %{job: nil, name: "Foo"},
  999 => %{job: "Bar", name: nil}}
}

在此先感谢您的帮助!

Answer 1

一个简单的解决方案:从两个映射中获取所有键，迭代键，从映射中检索值并构造元组 {key, %{name: name, job: job}} ，然后将元组缩减为映射。

name_map = %{
  105 => "Jim",
  48 => "Maria",
  62 => "Karen",
  888 => "Foo"
}

job_map = %{
  105 => "Social worker",
  48 => "Programmer",
  62 => "Teacher",
  999 => "Bar"
}

combined_map = Map.keys(name_map) ++ Map.keys(job_map)
               |> Stream.uniq
               |> Stream.map(&{&1, %{name: name_map[&1], job: job_map[&1]}})
               |> Enum.into(%{})

%{48 => %{job: "Programmer", name: "Maria"},
  62 => %{job: "Teacher", name: "Karen"},
  105 => %{job: "Social worker", name: "Jim"}, 
  888 => %{job: nil, name: "Foo"},
  999 => %{job: "Bar", name: nil}}