Retrieve array values inside foreach() loop - php

Question

I am trying to output Wordpress' navigation menu items along with their CSS Classes.
I was able to get the menu items, but the classes are more complicated. the css classes come in an array but it's already inside a foreach() loop.
$menu_items = wp_get_nav_menu_items($menu->term_id);
$menu_list = '<ul id="menu-' . $menu_name . '">';
foreach ( (array) $menu_items as $key => $menu_item ) {
$title = $menu_item->title;
$url = $menu_item->url;
$classes = $menu_item->classes;
$menu_list .= '<li>';
$menu_list .= '<i class=""></i>';
$menu_list .= '' . $title . '';
$menu_list .= '</li>';
}
$menu_list .= '</ul>';
As you can see, inside the foreach() loop I am getting the $title and $url which are both strings. But then when I try to get the css classes associated with the menu item through $menu_item->classes it returns an array and I am not sure how to do this.
Because each menu item has 3 css classses fa fa-user fa-3x I can return the values using this
$classes[0] . $classes[1] . $classes[2]
But suppose I don't want the third class and I leave it out empty, I get a missing offset error.
I also tried doing a foreach within the original foreach
$menu_list .= '<li>';
foreach($classes as $class) {
$menu_list .= '<i class="'. $class .'"></i>';
}
$menu_list .= '' . $title . '';
$menu_list .= '</li>';
But this returns 3 separate <i> tags for each menu item, which is not what I want. The output looks like this
<i class="fa"></i>
<i class="fa-user"></i>
<i class="fa-3x"></i>

Answer 1

Simply use a nested Loop in place like so:
<?php
$menu_items = wp_get_nav_menu_items($menu->term_id);
$menu_list = '<ul id="menu-' . $menu_name . '">';
foreach ( (array) $menu_items as $key => $menu_item ) {
$title = $menu_item->title;
$url = $menu_item->url;
$classes = $menu_item->classes;
$comboClass = "";
// USING NESTED LOOP CONSTRUCT
foreach($classes as $class){
$comboClass .= $class . " "; // SEPARATE CLASS-NAME WITH A SPACE
}
$menu_list .= '<li>';
$menu_list .= '<i class="' .$comboClass . '"></i>';
$menu_list .= '' . $title . '';
$menu_list .= '</li>';
}
$menu_list .= '</ul>';

Answer 2

You can nest loops...
foreach(...) {
... html stuff ..
echo '<div class="';
foreach($classes as $class) {
echo $class, ' ';
}
echo '">...</div>';
}