# unique方法 返回集合中所有唯一的項目。返回的集合保留著原數組的鍵，所以在這個例子中，我們會使用 [values](/collections/values.md) 方法來把鍵重置為連續編號的索引。 ``` $collection = collect([1, 1, 2, 2, 3, 4, 2]); $unique = $collection->unique(); // [ 0 => 1, 2 => 2, 4 => 3, 5 => 4]; $unique->values()->all(); // [1, 2, 3, 4] ``` 處理嵌套數組或對象時，你可以指定用來決定唯一性的鍵： ``` $collection = collect([ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'iPhone 5', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Apple Watch', 'brand' => 'Apple', 'type' => 'watch'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ['name' => 'Galaxy Gear', 'brand' => 'Samsung', 'type' => 'watch'], ]); $unique = $collection->unique('brand'); $unique->values()->all(); /* [ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ] */ ``` 你也可以傳入自己的回調來確定項目的唯一性： ``` $collection = collect([ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'iPhone 5', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Apple Watch', 'brand' => 'Apple', 'type' => 'watch'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ['name' => 'Galaxy Gear', 'brand' => 'Samsung', 'type' => 'watch'], ]); $unique = $collection->unique(function ($item) { return $item['brand'].$item['type']; }); $unique->values()->all(); /* [ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Apple Watch', 'brand' => 'Apple', 'type' => 'watch'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ['name' => 'Galaxy Gear', 'brand' => 'Samsung', 'type' => 'watch'], ] */ ``` > 在檢查項目值時 `unique` 方法使用的是「寬松」比較，意味著具有整數值的字符串將被視為等于相同值的整數。使用 [uniqueStrict](/collections/uniqueStrict.md) 可以進行「嚴格」比較 。