# mapWithKeys方法 遍歷集合并將每個值傳入給定的回調。回調應該返回包含一個鍵值對的關聯數組 ``` $collection = collect([ [ 'name' => 'John', 'department' => 'Sales', 'email' => 'john@example.com' ], [ 'name' => 'Jane', 'department' => 'Marketing', 'email' => 'jane@example.com' ] ]); $keyed = $collection->mapWithKeys(function ($item) { return [$item['email'] => $item['name']]; }); $keyed->all(); /* [ 'john@example.com' => 'John', 'jane@example.com' => 'Jane', ] */ ```