How to convert map keys from strings to atoms in Elixir

Question

What is the way to convert %{\"foo\" => \"bar\"} to %{foo: \"bar\"} in Elixir?

Answer 1

when you have a map inside another map

def keys_to_atom(map) do
 Map.new(
  map,
  fn {k, v} ->
    v2 = cond do
      is_map(v) -> keys_to_atom(v)
      v in [[nil], nil] -> nil
      is_list(v) -> Enum.map(v, fn o -> keys_to_atom(o) end)
      true -> v
    end
    {String.to_atom("#{k}"), v2}
  end
 )
end

sample:

my_map = %{"a" => "1", "b" => [%{"b1" => "1"}], "c" => %{"d" => "4"}}

result

%{a: "1", b: [%{b1: "1"}], c: %{d: "4"}}

note: the is_list will fail when you have "b" => [1,2,3] so you can comment/remove this line if this is the case:

# is_list(v) -> Enum.map(v, fn o -> keys_to_atom(o) end)