php - PHP公告: Undefined index: in a line

Question

我知道很多人都问过这个问题，但我的工作不兼容:

if(isset($instance['threadnumbers'] == "")){ $instance['threadnumbers'] == "" }

它显示以下调试错误:

PHP Notice: Undefined index: threadnumbers in /home/content/59/12158859/html/development/wp-content/plugins/dpt/disqus-ptw.php on line 27

该区域如下:

if ($instance['threadnumbers'] == NULL) {
    $instance['threadnumbers'] = "5";
}

如何解决？非常感谢 :)

Answer 1

您有剪切和粘贴错误。您正在尝试使用比较运算符分配值。 ==应该是=。

您还在作业上使用isset()。

if(isset($instance['threadnumbers'])){ $instance['threadnumbers'] == "" }

应该

if(!isset($instance['threadnumbers']) || empty($instance['threadnumbers'])) { 
    $instance['threadnumbers'] = ""; 
}