Laravel blade 模板的 @foreach 循环中，对集合使用 groupBy 函数的方法

Laravel 框架中集合的groupBy 方法可以根据指定键对集合项进行分组：

$collection = collect([
    ['account_id' => 'account-x10', 'product' => 'Chair'],
    ['account_id' => 'account-x10', 'product' => 'Bookcase'],
    ['account_id' => 'account-x11', 'product' => 'Desk'],
]);

$grouped = $collection->groupBy('account_id');

$grouped->all();

/*
    [
        'account-x10' => [
            ['account_id' => 'account-x10', 'product' => 'Chair'],
            ['account_id' => 'account-x10', 'product' => 'Bookcase'],
        ],
        'account-x11' => [
            ['account_id' => 'account-x11', 'product' => 'Desk'],
        ],
    ]
*/

那么，我们如果在后台的时候不方便对集合进行groupBy操作，也可以在模板中调用groupBy：

@foreach($collection->groupBy('account_id) as $account_id => $group)
    {{ $account_id }}
    @foreach($group as $value)
        {{ $value->product }}
    @endforeach
@endforeach