Laravel 5.2 Foreach 按日期排序

Question

我创建了一个显示 Post 的视图以及对 post 的回复。对于这个问题，回复是在一个 foreach 循环中并以随机顺序进行的。有没有办法对 foreach 循环进行排序，以便最早的回复位于顶部？最旧的回复在底部？

这是循环

 @foreach($topic->replies as $reply)
         <div class="collection">
            <div class="collection-item row">
               <div class="col s3">
                  <div href="" class="avatar collection-link">
                     <div class="row">
                        <div class="col s3"><img src="/uploads/avatars/{{ $reply->user->avatar }}" alt="" class="circle" style="width: 50px;"></div>
                           <div class="col s9">
                              <p class="user-name">{{ $reply->user->username }}</p>
                           </div>
                        </div>
                              <p>Role: {{ $reply->user->role->role_name }}</p>
                              <p>Since: {{ $reply->user->created_at }}</p>
                              <p class="post-timestamp">Posted on: {{ $reply->created_at }}</p>
                     </div>
                   </div>
                   <div class="col s9">
                      <div class="row last-row">
                        <div class="col s12">
                           <p>{!! $reply->reply_text !!}</p>
                        </div>
                      </div>
                      <div class="row last-row block-timestamp">
                        <div class="col s6">
                           <p class="post-timestamp">Last changed: {{ $reply->updated_at }}</p>
                        </div>
                      </div>
                 </div>
             </div>
         </div>
 @endforeach

TopicsController.php（显示方法）

public function show($theme_id, $topic_id)
{
    $theme = Theme::with('topics')->findOrFail($theme_id);
    $topic = Topic::with('theme')->findOrFail($topic_id);

    return view('topics.topic')->withTopic($topic)->withTheme($theme);

}

提前致谢！

Answer 1

所有 Eloquent 查询 return Laravel collections. So you can use the sortBy 函数在 foreach 中排序您的回复。

@foreach($topic->replies->sortByDesc('created_at') as $reply)

但是，更好的解决方案是在查询中对您的回复进行排序。这可以通过像这样更新您的 Eloquent 查询来实现：

$topic = Topic::with([
    'theme',
    'replies' => function ($query) {
        $query->orderByDesc('created_at');
    }
])
->findOrFail($topic_id);

Answer 2

public function show($theme_id, $topic_id)
{
    $theme = Theme::with([
        'topics' => function($query) {
            $query->orderBy('replies');
        }
    ])->findOrFail($theme_id);

    $topic = Topic::with('theme')->findOrFail($topic_id);

    return view('topics.topic')->withTopic($topic)->withTheme($theme);

}

https://laravel.com/docs/5.4/eloquent-relationships#constraining-eager-loads

Answer 3

对我来说，最干净的选择是，在您的 Topic 模型中，默认使用 created_at 时间戳对关系结果进行排序，如下所示：

class Topic
{
    public function replies()
    {
        return $this->hasMany('Reply')->orderBy('created_at','desc');
    }
}

这样您之后就不需要对集合进行排序，让 sql 完成工作，从而使代码更轻，性能更好，因为您几乎每次都需要以这种方式排序的主题.

这还有一个好处是您共享的代码可以保持不变，但我建议您在控制器中预先加载关系（以避免执行不必要的查询）：

$topic = Topic::with(['theme','replies'])->findOrFail($topic_id);

希望对您有所帮助。

Laravel 5.2 Foreach 按日期排序

Laravel 5.2 Foreach order by date

php

foreach

laravel

laravel-5

laravel-5.2