嗯......我遇到了一个未定义的错误

-3

我在做关于使用foreach和for循环在PHP中打印表格的LAB练习。但我现在已经遇到了这个问题。嗯......我遇到了一个未定义的错误

The question let me to print a table like this.

这里是我的代码：

<?php 

     $subjects = array(
      "sem1" => array("Prog", "DP", "NF", "ENG", "SDD"), 
      "sem2" => array("IP", "DMS", "OOP", "SA"), 
      "sem3" => array("INSP", "SAP", "ITP"), 
     ); 

     //maximum number of subjects 
     $maxSubNum = 10; 

     //creating table 
     echo "<table border='1'>"; 
      //loop the array 
      foreach ($subjects as $sem => $subjectArray) { 
       //print <tr> 
       echo "<tr>"; 
       //print semeester number in <td>, bold the text 
       echo "<td><b>$sem</b></td>\n"; 
       //loop 10 times 
       for ($i=0; $i < $maxSubNum; $i++) { 
        //check if subject exists 
        if (isset($subjectArray)) { 
         //print subject in <td> 
         echo "<td>$subjectArray[$i]</td>\n"; 
        } else { 
         //print empty in <td> 
         echo "<td></td>\n"; 
        } 
       } 
       //closing <tr> 
       echo "</tr>\n"; 
      } 
     echo "</table>\n"; 

     ?>

Finally, it warns me those notices although I can print out he table.

任何人都可以帮助吗？请？

来源

2017-02-27 Harris Chan

而哪一行是32行？ – arkascha

只需检查'isset（$ subjectArray [$ i]）'。您的循环迭代10次，而您的数组中的元素数量少于此数量。这就是为什么你得到undefine抵消通知 –

回声“$ subjectArray [$ i] \ n”; 这是行32 –

你sem1,2和3分分别列在其中5,4,3元素。但是，当你定义$ maxSubnum = 10时，php正在寻找其他的元素。

请尝试以下操作。

<?php 

     $subjects = array(
      "sem1" => array("Prog", "DP", "NF", "ENG", "SDD"), 
      "sem2" => array("IP", "DMS", "OOP", "SA"), 
      "sem3" => array("INSP", "SAP", "ITP"), 
     ); 



     //creating table 
     echo "<table border='1'>"; 
      //loop the array 
      foreach ($subjects as $sem => $subjectArray) { 
       //print <tr> 
       echo "<tr>"; 
       //print semeester number in <td>, bold the text 
       echo "<td><b>$sem</b></td>\n"; 
       //don't have to loop 10 times 
       //maximum number of subjects 
       $maxSubNum = count($subjectArray); 
       for ($i=0; $i < $maxSubNum; $i++) { 
        //check if subject exists 
        if (isset($subjectArray)) { 
         //print subject in <td> 
         echo "<td>$subjectArray[$i]</td>\n"; 
        } else { 
         //print empty in <td> 
         echo "<td></td>\n"; 
        } 
       } 
       //closing <tr> 
       echo "</tr>\n"; 
      } 
     echo "</table>\n"; 

     ?>

来源

2017-02-27 10:51:05

您正在使用循环不maxSubNum错误的限制，但数（$ subjectArray）

for ($i=0; $i < count($subjectArray)-1; $i++) {

来源

2017-02-27 10:50:18 scaisEdge

嗯......我遇到了一个未定义的错误

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