我想删除名为$subPages的嵌套列表，使其不显示在所有名为$pages的顶级列表下，但Services除外。
我的尝试是允许嵌套列表项显示在所有三个顶级项下。

如何从所有顶层列出的项目中删除嵌套导航，只有一个例外，即“Services”仅在PHP中使用数组？

<nav class="navBar wAuto fRight positAb">
        <?php
            $pages = array(
            '/about/' => 'About',
            '/services/' => 'Services',
            '/book-a-service/' => 'Book a service'
            );

            $subPages = array(
            '/services/bathroom-installation' => 'Bathroom installation',
            '/services/boiler-repair' => 'Boiler repair',
            '/services/boiler-service' => 'Boiler service',
            '/services/gas-oil' => 'Gas &amp; oil',
            '/services/heat-recovery' => 'Heat recovery',
            '/services/heating-plumbing' => 'Heating and plumbing',
            '/services/rainwater-harvesting' => 'Rainwater harvesting',
            '/services/solar-solutions' => 'Solar solutions',
            '/services/underfloor-heating' => 'Underfloor heating'
            );
            $activePage = $_SERVER['REQUEST_URI'];
            //open nav

        foreach( $pages as $url => $anchor){
            $activeClass = ($_SERVER['REQUEST_URI'] == $url) ? " active" : "";
            echo '<li class="fLeft"><a class="font13'.$activeClass.'" href="'.$url.'"';

            if($url == '/services/'){
                echo 'id="parent"';
            };

            if($url == '/book-a-service/'){
                echo 'id="ctaUHP"';
                echo '>'.$anchor.'</a>';
                //Open nested nav
            };

            if(isset($url) == '/services/'){
                echo '<ul class="wAuto positAb">';
                foreach($subPages as $url => $anchor){
                    echo '<li class="fullWidth"><a class="font10" href="'.$url.'"';//open nested nav
                    echo '>'.$anchor.'</a></li>';
                }
            };

            //Close nested nav
            echo '</li></ul>';
            //Close submenu
        }

        //Close nav
        echo '</ul>';
     ?>
    </nav>