CODEWITHSUNDEEP
elixir
simo
simo

Reputation: 24560

Iterate through multiple keys on map

I have this code:

          {drop_off_lat, _ } = case student_model.drop_off_lat do
            nil -> {0.0, 0}
            value -> {Float.parse(value), 0}
          end

          {drop_off_lng, _ } = case student_model.drop_off_lng do
            nil -> {0.0, 0}
            value -> {Float.parse(value), 0}
          end

          {pick_up_lat, _ } = case student_model.pick_up_lat do
            nil -> {0.0, 0}
            value -> {Float.parse(value), 0}
          end

          {pick_up_lng, _ } = case student_model.pick_up_lng do
            nil -> {0.0, 0}
            value -> {Float.parse(value), 0}
          end

for each key (drop_off_lat, drop_off_lng, pick_up_lat, pick_up_lng) I am checking if its nil to replace with 0, otherwise to replace with float parsing of its version.

Although its working, but I feel that the code can be more compact with fewer lines, right?

Upvotes: 0

Views: 107

Answers (1)

Dogbert
Dogbert

Reputation: 222118

You can use for and pattern match its return value:

map = %{
  drop_off_lat: nil,
  drop_off_lng: "4.5",
  pick_up_lat: "6.5e2",
  pick_up_lng: nil,
}


[drop_off_lat, drop_off_lng, pick_up_lat, pick_up_lng] =
  for key <- [:drop_off_lat, :drop_off_lng, :pick_up_lat, :pick_up_lng] do
    case map[key] do
      nil -> 0.0
      value -> String.to_float(value)
    end
  end

IO.inspect {drop_off_lat, drop_off_lng, pick_up_lat, pick_up_lng}

Output:

{0.0, 4.5, 650.0, 0.0}

Upvotes: 1

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