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在Laravel视图中使用foreach变量

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我的MySQL表看起来像这样（相关部分）：

student_id (int) | engmins(int) | totalmins(int) | created_at (datetime)    
1                | 50           | 100            | 2017-12-15 00:00:00
1                | 20           | 45             | 2017-12-15 00:00:00

我有以下代码：

$students = StudentDetails::with('student','studentschool','classactivity')
    ->where('class', 1)
    ->orderBy('studentgrade', 'DESC')
    ->get();

$calculatePercentage = array();

foreach ($students as $s) 
{
    $fetchEngClassPercents= DB::table('ClassActivity')
    ->select(DB::raw('round((sum(engmins) * 60) / (sum(totalmins) * 60) * 100) as percents'))
    ->where('created_at', '>=', Carbon::now()->subDays(30))
    ->where('student_id', '=', $s->student->id)->get();     
    foreach($fetchEngClassPercents as $f)
    {
        $calculatePercentage = $f->percents;
        var_dump($calculatePercentage); //Debug purposes
    }
}

var_dump($calculatePercentage);  //Debug purposes

$params = [
    'engClassPercentage' => $calculatePercentage,
    'studentInfo'        => $students,
];

return view('user.classes.engclass.index', $params);

  • var_dump INSIDE循环执行 string(2) "43" NULL

  • var_dump OUTSIDE循环执行 NULL

这是它在视图中的样子：

<td>
    @foreach($engClassPercentage as $p)
        {{ $p->percents }}
    @endforeach
</td>

This doesn't work in the view, it simply shows nothing.

由于某种原因，$ calculatePercentage在循环之外保持为null（在之前尝试转储var时） . 当它在foreach循环中时，它执行查询 .

奇怪的是，我声明循环外的数组（$ calculatePercentage）在foreach循环中赋值变量 .

说实话，我很遗憾，如果能得到帮助，我会很高兴 .

php laravel foreach blade laravel-blade

3 回答

  • 2

    改变$ calculatePercentage = $ f-percents;喜欢下面 . 然后在foreach部分将$ p->百分比更改为$ p .

    $calculatePercentage[] = $f->percents;

@foreach($engClassPercentage as $p)
   {{$p}}
@endforeach
    回复于
  • 0

    $ calculatePercentage在每个循环中被覆盖，将其更改为数组键

    $calculatePercentage[] = $f->percents;

    然后在你的foreach中调用$ params数组

    @foreach($params['engClassPercentage'] as $p)
    回复于
  • 2

    您没有存储在foreach循环中计算的值：

    因此，值不会根据您的要求持续存在 .

    更新的代码：

    foreach ($students as $s) 
{
    $fetchEngClassPercents= DB::table('ClassActivity')
    ->select(DB::raw('round((sum(engmins) * 60) / (sum(totalmins) * 60) * 100) as percents'))
    ->where('created_at', '>=', Carbon::now()->subDays(30))
    ->where('student_id', '=', $s->student->id)->get();     
    foreach($fetchEngClassPercents as $f)
    {
        $calculatePercentage[] = $f->percents; // <-- This line is edited.
    }
}
    回复于

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