让我们先看看这一部分：

我不太明白什么东西$item 这可能就是问题所在。当我打电话时get_class() 在…上$item 我明白了WP_Post, 但是WP_Post 没有classes属性。那么$item->classes 返回类数组？

关于WordPress中菜单结构的几点注意事项：

每个导航菜单在nav_menu 分类学

然后，当我们向该菜单添加项目时，我们正在创建该类型的新post对象nav_menu_item.

每个菜单的树结构不是存储在post_parent 的字段nav_menu_item 职位，如预期。我们实际上在post meta表中找到了它，它存储在_menu_item_menu_item_parent 元键，针对每个nav_menu_item 邮递

在$item 菜单项数据对象是修饰的WP_Post 对象，即使用wp_setup_nav_menu_item() 功能：

/**
 * Decorates a menu item object with the shared navigation menu item properties.
 *
 * Properties:
 * - ID:               The term_id if the menu item represents a taxonomy term. 
 * - attr_title:       The title attribute of the link element for this menu item.
 * - classes:          The array of class attribute values for the link element of this menu item.
 * - db_id:            The DB ID of this item as a nav_menu_item object, if it exists (0 if it doesn\'t exist).
 * - description:      The description of this menu item.
 * - menu_item_parent: The DB ID of the nav_menu_item that is this item\'s menu parent, if any. 0 otherwise.
 * - object:           The type of object originally represented, such as "category," "post", or "attachment."
 * - object_id:        The DB ID of the original object this menu item represents, e.g. ID for posts and term_id for categories.
 * - post_parent:      The DB ID of the original object\'s parent object, if any (0 otherwise).
 * - post_title:       A "no title" label if menu item represents a post that lacks a title.
 * - target:           The target attribute of the link element for this menu item.
 * - title:            The title of this menu item.
 * - type:             The family of objects originally represented, such as "post_type" or "taxonomy."
 * - type_label:       The singular label used to describe this type of menu item.
 * - url:              The URL to which this menu item points.
 * - xfn:              The XFN relationship expressed in the link of this menu item.
 * - _invalid:         Whether the menu item represents an object that no longer exists.

使用类后search-class 要查找该项目，我想将其从该项目中删除。然而，我的电话unset($item->classes[$class_key]); 不起作用。

从中删除类为时已晚$item 对象，在nav_menu_link_attributes 筛选，以便从菜单项（li标记）中删除类。

例如，我们可以使用nav_menu_css_class 筛选以修改这些类。

一般来说，使用这样的过滤器而不是直接修改数据对象可能是更好的方法，因为其他插件可能依赖于原始数据对象

下面是一个如何删除search-class 类别：

add_filter( \'nav_menu_css_class\', function( $classes, $item, $args, $depth )
{
    return array_filter(
        (array) $classes, 
        function( $val ) { return \'search-class\' !== $val; } 
    ); 

}, 10, 4 );

add_filter( \'nav_menu_link_attributes\', function( $atts, $item, $args )
{
    // Nothing to do
    if( 
           ! isset( $item->classes ) 
        || ! in_array( \'klasi1\', $item->classes, true ) 
        || ! isset( $atts[\'class\'] ) 
    )
        return $atts;

    // Add data attribute to anchor tag
    $atts[\'data-something\'] = \'something\';

    // Append an anchor class
    $classes = explode( \' \', $atts[\'class\'] );
    $classes[] = \'something-class\';
    $atts[\'class\'] = join( \' \', array_filter( $classes ) );

    return $atts;
}, 10, 3 );