按Elixir中的多个值映射分组

Enum.group_by(collection, key_fun, value_fun)

data = [
  %{name: "Alice", age: 25, city: "New York"},
  %{name: "Bob", age: 30, city: "London"},
  %{name: "Charlie", age: 25, city: "New York"},
  %{name: "Dave", age: 35, city: "London"}
]

result = Enum.group_by(data, fn %{age: age, city: city} -> {age, city} end, fn %{name: name} -> name end)

IO.inspect(result)

%{
  {25, "New York"} => ["Alice", "Charlie"],
  {30, "London"} => ["Bob"],
  {35, "London"} => ["Dave"]
}