PHP 偏移量错误

Question

我遇到了一个 PHP 错误，通过我在 Internet 上的所有搜索，我一直无法破解。

错误提示：

Error message Notice: Undefined offset: 3 in include() (line 89 of /home/devced/public_html/site/sites/all/themes/cedncsu/page.tpl.php).

所以，看看我的代码，我目前有（实际使用在下面评论）：

<?php
    // Get Base URL
    global $base_url;

    // Get the Page's Parent Menu Item
    $menuParent = menu_get_active_trail();

    // Since it returns an array, make sure to target what you are looking for
    // You should print_r what menu_get_active_trail() to see what else it gives you
    $menuParent = $menuParent[1]['link_title'];
    $menuParent = strtolower(str_replace( " ", "-", $menuParent));
    $menuParent = preg_replace('/[^\w\d_ -]/si', '', $menuParent);

    // Generate class specific for department page headers
    $menuParentDepartment = menu_get_active_trail();
    $menuParentDepartment = $menuParentDepartment[3]['link_title']; // This is where they say the error is
    $menuParentDepartment = strtolower(str_replace( " ", "-", $menuParentDepartment));
    $menuParentDepartment = preg_replace('/[^\w\d_ -]/si', '', $menuParentDepartment);

    // Current Page space replace/lowercase
    $currentTitle = strtolower(str_replace( " ", "-", $title));
    $currentTitle = preg_replace('/[^\w\d_ -]/si', '', $currentTitle);
?>

我认为这是我所缺少的一般编码实践，但迄今为止一直被难住了。任何帮助将不胜感激。谢谢！

Answer 1

很简单：$menuParentDepartment[3] 没有定义。在尝试索引它之前，您需要确保索引（或 PHP 称之为偏移量）存在。使用isset。