php - 我如何将 array_column 值传递给另一个数组 - PHP

Question

我正在为我的出勤报告生成 csv 文件，这是我关于选择所有学生及其日志的查询:

    $students = User::has('userStudentAttendance')->with(['userStudentAttendance' => function($query) use ($details,$search_from, $search_to){
        $query->where('status', $details);
        $query->where(function($query) use ($search_from, $search_to){
            $query->whereBetween(DB::raw('Date(created_at)'), [$search_from, $search_to]);
        });
        $query->groupby('user_id')->groupby(DB::raw('Date(created_at)'));
    }])
    ->leftjoin('sys_user_student', 'sys_user_student.user_id', '=', 'sys_user.user_id')
    ->leftjoin('sys_mf_section', 'sys_mf_section.section_id', '=', 'sys_user_student.section_id')
    ->leftjoin('sys_mf_grade', 'sys_mf_grade.grade_id', '=', 'sys_mf_section.grade_id')     
    ->where('user_type_id', '4')
    ->where('sys_mf_section.section_id', $request->getParam('section_id'))
    ->where('sys_mf_grade.grade_id', $request->getParam('grade_id'))    
    ->orderBy('sys_user.last_name') 
    ->get();

    if ($students->count() > 0)
    {

        echo "<pre>";
        var_dump($test_array);
        exit();

        $csv = $this->csv;

        $csv->exportHeader('attendance (' . date_format(date_create($request->getParam('search_from')),"M-d-Y") . ' - ' . date_format(date_create($request->getParam('search_to')),"M-d-y") . ')');
        $csv->startInstance();

        $csv->addRow([                  
                'Student No.',
                'Fullname',
                'Gender',
                'Date & Time'
            ]);

        foreach ($students as $student) {

            $logs = $student->userStudentAttendance;
            $logs_array = array_column($logs, 'created_at');

            $csv->addRow([                  
                $student->identification_number,
                $student->last_name.", ".$student->first_name,
                $student->gender,
                $student->userStudentAttendance
            ]);
        }

        $csv->endInstance();

        die();
    }

$userStudentAttendance 给出了一个 json 对象，所以为了在 php 中显示它，我使用了

$logs = json_decode($userStudentAttendance)

将其转换为关联数组，然后我将其转换为 array_column 以获得我想要显示的唯一列

$logs_array = array_column($logs, 'created_at')

然后我在 $csv->addRow([])

中更改了 $student->userStudentAttendance

现在看起来像这样:

         foreach ($students as $student) {

            $csv->addRow([                  
                $student->identification_number,
                $student->last_name.", ".$student->first_name,
                $student->gender,
                $logs_array
            ]);
        }

然后现在将其转换为 csv 时，$logs_array 行为空。怎么了？谁能帮我？提前致谢

Answer 1

我想，addRow 期望参数数组的每一项都是字符串，因此可以将其放入 csv 文件中。您对 array_column 的调用返回数组，这不是字符串。这就是为什么您需要 内爆 数组值，例如:

$csv->addRow([                  
    $student->identification_number,
    $student->last_name.", ".$student->first_name,
    $student->gender,
    implode(',', $logs_array)    // Here we implode values
]);