# collection中sum求和 ## 计算下列数组中`order_products`下数组元素`price`的和 开始前，使用 `composer require illuminate/support`，获得collect的相关支持。 ``` <?php // 引入package require __DIR__ . '/vendor/autoload.php'; $orders = [[ 'id' => 1, 'user_id' => 1, 'number' => '13908080808', 'status' => 0, 'fee' => 10, 'discount' => 44, 'order_products'=> [ ['order_id'=>1,'product_id'=>1,'param'=>'6寸','price'=>555.00,'product'=>['id'=>1,'name'=>'蛋糕名称','images'=>[]]], ['order_id'=>1,'product_id'=>1,'param'=>'7寸','price'=>333.00,'product'=>['id'=>1,'name'=>'蛋糕名称','images'=>[]]], ], ]]; ``` ### 使用foreach循环数据 ``` $price = 0; foreach ($orders as $order) { foreach($order['order_products'] as $ordert_product){ $price += $ordert_product['price']; } } dd($price); ``` > 声明临时变量记录总价格，配合两次循环获得总价并累计。 ### 将上面的方式改成collection的[map](/collections/map.md)、[flatten](/collections/flatten.md)和[sum](/collections/sum.md)方式 ``` collect($orders)->map(function($order){ return $order['order_products']; })->flatten(1)->map(function($order){ return $order['price']; })->sum(); ``` ### 将上面的求解方式改成collection的[flatMap](/collections/flatMap.md)、[pluck](/collections/pluck.md)和[sum](/collections/sum.md)方式 ``` collect($orders)->flatMap(function($order){ return $order['order_products']; })->pluck('price')->sum(); ``` ### 将上面的求解方式改成collection的[flatMap](/collections/flatMap.md)和[sum](/collections/sum.md)方式 ``` collect($orders)->flatMap(function($order){ return $order['order_products']; })->sum('price'); ```