在我的laravel 5.7中，我尝试使用collection重新制作一小部分应用程序

$selectedSubscriptions = [1,2,3];
$siteSubscriptionsList = [];
$siteSubscriptions     = SiteSubscription
    ::getByActive(true)
    ->orderBy('id', 'asc')
    ->get();
foreach ($siteSubscriptions as $next_key => $nextSiteSubscription) {
    $is_found = false;
    foreach ($selectedSubscriptions as $next_value) {
        if ($nextSiteSubscription->id == (int)$next_value) {
            $is_found = true;
            break;
        }
    }
    $siteSubscriptionsList[] = (object)['name' => $nextSiteSubscription->name, 'id' => $nextSiteSubscription->id, 'checked' => $is_found];
}

喜欢 ：

$selectedSubscriptions = [1,2,3];
$siteSubscriptionsList     = SiteSubscription
    ::getByActive(true)
    ->orderBy('id', 'asc')
    ->get()
    ->map(function ( $item, $selectedSubscriptions ) {
        $is_found = false;
        foreach ($selectedSubscriptions as $next_value) {
            if ($item->id == (int)$next_value) {
                $is_found = true;
                break;
            }
        }
        return (object)['name' => $item->name, 'id' => $item->id, 'checked' => $is_found];

    })
    ->all();

但是我需要将附加参数$selectedSubscriptions设置为map函数，因为它不起作用，因为我在os中看到了map 该功能的值为“ 0”。 如何正确？

分析解答

将数据传递到->map()闭包时，可以使用use语句（在function()调用之后）：

$selectedSubscriptions = [1,2,3];
$siteSubscriptionsList = SiteSubscription
    ::getByActive(true)
    ->orderBy('id', 'asc')
    ->get()
    ->map(function ($item, $key) use ($selectedSubscriptions) {
        $is_found = false;
        foreach ($selectedSubscriptions as $next_value) {
            if ($item->id == (int)$next_value) {
                $is_found = true;
                break;
            }
        }
        return (object)['name' => $item->name, 'id' => $item->id, 'checked' => $is_found];

    })
    ->all();

->map()的第二个参数将始终是$key的变量。

旁注：您可以使用以下方法减少ID的foreach检查：

$is_found = collect($selectedSubscriptions)->contains($item->id);