# collection中reduce創建lookup數組 有如下數組 ``` $employees = [ [ 'name' => 'example', 'email' => 'example@exmaple.com', 'company' => 'example Inc.' ], [ 'name' => 'Lucy', 'email' => 'lucy@example.com', 'company' => 'ibm Inc.' ], [ 'name' => 'Taylor', 'email' => 'toylor@laravel.com', 'company'=>'Laravel Inc.' ] ]; ``` 通過計算將其轉化成如下格式 ``` $lookup = [ 'example' => 'example@example.com', 'Lucy' => ‘lucy@example.com’, 'Taylor'=> 'toylor@laravel.com' ]; ``` ## 使用foreach解決 ``` $emails = []; foreach ($employees as $key => $value) { $emails[$value['name']] = $value['email']; } dd($emails); ``` ## 使用collection的[reduce](/collections/reduce.md)方法 ``` $emails = collect($employees)->reduce(function($emailLookup, $employee){ $emailLookup[$employee['name']] = $employee['email']; return $emailLookup; },[]); dd($emails); ``` ## 使用 [pluck](/collections/pluck.md) 方法 ``` $emails = collect($employees)->pluck('name', 'email'); dd($emails); ```