生成后如何在excel上显示数据值？ Codeigniter PHP

Question

我正在尝试将数据库中的值显示到 excel 表，问题是我有一个undefined offset error

问题从这里开始：

代码： enrollmentID是我识别每个值的关键，foreach 是未定义偏移量所在的问题。 有没有办法解决这个问题，以便我可以在 excel 中显示我的数据？

if($key == 'enrollmentID'){
    $intLec = 0;                    
    $intLab = 0;                                     

    foreach ($enrollmentSubjectListData[$value]['subjectCode'] as $subjKey => $subjValue) {
        $coordinates = $this->getExcelColumnConversion($col) . $row;
        $this->excel->getActiveSheet()->setCellValue($coordinates, $subjValue);
        $col++; 

        $coordinates = $this->getExcelColumnConversion($col) . $row;
        $this->excel->getActiveSheet()->setCellValue($coordinates, $enrollmentSubjectListData[$value]['numericalEquivalent'][$subjKey]);
        $col++; 
        
        if($enrollmentSubjectListData[$value]['lab'][$subjKey] != 0)
            $units = $enrollmentSubjectListData[$value]['lec'][$subjKey] . '/' . $enrollmentSubjectListData[$value]['lab'][$subjKey];
        else
            $units = $enrollmentSubjectListData[$value]['lec'][$subjKey];

        $coordinates = $this->getExcelColumnConversion($col) . $row;
        $this->excel->getActiveSheet()->setCellValue($coordinates, $units);
        $col++;

        $intLec += (float)str_replace(array( '(', ')' ), '', $enrollmentSubjectListData[$value]['lec'][$subjKey]);                                                                                        
        $intLab += (float)$enrollmentSubjectListData[$value]['lab'][$subjKey];
    }
    
    if($intLab == 0){
        $coordinates = $this->getExcelColumnConversion($col) . $row;
        $this->excel->getActiveSheet()->setCellValue($coordinates, $intLec);
    }
    else{
        $coordinates = $this->getExcelColumnConversion($col) . $row;
        $this->excel->getActiveSheet()->setCellValue($coordinates, $intLec . '/' . $intLab);
    }
}

Answer 1

undefined offset错误通常意味着您尝试在数组中检索的键不存在。

在这里，如果在foreach语句中抛出错误，原因可能是：

• $enrollmentSubjectListData数组中不存在 $value 键
• 或者， $enrollmentSubjectListData[$value]不包含'subjectCode'键（或者只是$enrollmentSubjectListData[$value]不是数组）

您可以实施的一个简单修复方法是用IF语句包围您的foreach ：

// Making sure that the $value key exists in the $enrollmentSubjectListData array
    if(key_exists($value,$enrollmentSubjectListData))
    {
        $valueArray = $enrollmentSubjectListData[$value];
    
        // Making sure that the $valueArray is an array and that the $valueArray['subjectCode'] key exists
        if(is_array($valueArray) && (key_exists('subjectCode',$valueArray)))
        {
            $subjectCodeArray = $valueArray['subjectCode'];
    
            // Making sure that the $subjectCodeArray is an array
                if(is_array($subjectCodeArray))
                {
                    foreach ($subjectCodeArray as $subjKey => $subjValue) {
                        $coordinates = $this->getExcelColumnConversion($col) . $row;
                        $this->excel->getActiveSheet()->setCellValue($coordinates, $subjValue);
                        $col++; 
                    
                        $coordinates = $this->getExcelColumnConversion($col) . $row;
                        $this->excel->getActiveSheet()->setCellValue($coordinates, $enrollmentSubjectListData[$value]['numericalEquivalent'][$subjKey]);
                        $col++; 
                        
                        if($enrollmentSubjectListData[$value]['lab'][$subjKey] != 0)
                            $units = $enrollmentSubjectListData[$value]['lec'][$subjKey] . '/' . $enrollmentSubjectListData[$value]['lab'][$subjKey];
                        else
                            $units = $enrollmentSubjectListData[$value]['lec'][$subjKey];
                    
                        $coordinates = $this->getExcelColumnConversion($col) . $row;
                        $this->excel->getActiveSheet()->setCellValue($coordinates, $units);
                        $col++;
                    
                        $intLec += (float)str_replace(array( '(', ')' ), '', $enrollmentSubjectListData[$value]['lec'][$subjKey]);                                                                                        
                        $intLab += (float)$enrollmentSubjectListData[$value]['lab'][$subjKey];
                    }
                }
            }
        }

请记住，这段代码只会防止您的代码崩溃，但不会告诉您为什么您的输入数据首先没有正确格式化。

为此，我建议您在 IDE 中使用调试器，例如 xDebug。