Question

寻找获得＆＃34; lat＆＃34;的最佳方法。和＆＃34; lon＆＃34;出于这个：

{:ok,
%Geocoder.Coords{
  bounds: %Geocoder.Bounds{
  bottom: 43.1949619,
  left: -86.2468396,
  right: -86.24483359999999,
  top: 43.19497399999999
},
 lat: 43.19497399999999,
 location: %Geocoder.Location{
 city: "Muskegon Heights",
 country: "United States",
 country_code: "US",
 formatted_address: "Amsterdam, Muskegon Heights, MI 49444, USA",
 postal_code: "49444",
 state: "Michigan",
 street: "Amsterdam",
 street_number: nil
},
lon: -86.24586719999999
}}

感谢您的建议。

Answer 1

你可以使用这样的模式匹配：

# assuming the value in your question is stored in `value`
{:ok, %{lat: lat, lon: lon}} = value
IO.inspect lat
IO.inspect lon

您还可以使用点来提取整个值并访问lat和lon：

{:ok, coords} = value
IO.inspect coords.lat
IO.inspect coords.lon

Answer 2

再次为了完整起见，似乎你也可以在这里使用Map.get / 3。

defmodule Geocoder.Bounds do
  defstruct [:bottom, :left, :right, :top]
end

defmodule Geocoder.Location do
  defstruct [
    :city,
    :country,
    :country_code,
    :formatted_address,
    :postal_code,
    :state,
    :street,
    :street_number
  ]
end

defmodule Geocoder.Coords do
  defstruct [:bounds, :lat, :location, :lon]
end

defmodule Test do
  alias Geocoder.{Bounds, Location, Coords}

  def new() do
    b = %Bounds{bottom: 43.19, left: -86, right: -86, top: 43}

    l = %Location{
      city: "abc",
      country: "usa",
      country_code: "usa",
      formatted_address: "",
      postal_code: "49444",
      state: "Michigan",
      street: "Amsterdam",
      street_number: nil
    }

    {:ok, %Coords{bounds: b, lat: 43.1, location: l, lon: -86.2}}
  end

  def get_lat() do
    g = new()
    elem(g, 1) |> Map.get(:lat)
  end

  def get_lon() do
    g = new()
    elem(g, 1) |> Map.get(:lon)
  end
end

虽然我认为@ dogbert的方法更好，但我再次提供这个只是为了提供一个潜在的选择。

BTW，我知道我没有使用与示例代码相同的所有值，但我厌倦了复制/粘贴示例中的代码。无论如何，其中的差异不应该是显着的。

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