And list

defmodule People do
  def list(people) do
    if Kernel.length(people) == 1 do
      Enum.at(people, 0)[:name]
    else
      Enum.map(people, fn person -> person[:name] end)
        |> Enum.join(", ")
        |> String.replace(~r/,([^,]+)$/, " &\\1")
    end
  end
end