如何刪除集合中的重複項？

Question

我在Laravel集合：

Collection {#450 ▼ 
    #items: array:2 [▼ 
    0 => Announcement {#533 ▶} 
    1 => Announcement {#553 ▶} 
    ] 
} 

它是同一個項目。如何刪除其中一個？

的完整代碼：

public function announcements() 
    { 

     $announcements = $this->categories_ann->map(function ($c) { 
      return $c->announcements->map(function ($a) { 
       $a->subsribed = true; 

       return $a; 
      }); 
     }); 

     $flattened = $announcements->groupBy("id")->flatten(); 

     return $flattened; 
    } 

Answer 1

$unique = $collection->unique();