Add class=“active” to active page using PHP

Add class=“active” to active page using PHP:

<ul id="mainnav">
    <li class="<?php if ($first_part=="") {echo "active"; } else  {echo "noactive";}?>"><a href="#">Home</a></li>
    <li class="<?php if ($first_part=="tutorials") {echo "active"; } else  {echo "noactive";}?>"><a href="#">Tutorials</a></li>
    <li class="<?php if ($first_part=="resources") {echo "active"; } else  {echo "noactive";}?>"><a href="#">Resources</a></li>
    <li class="<?php if ($first_part=="library") {echo "active"; } else  {echo "noactive";}?>"><a href="#">Library</a></li>
    <li class="<?php if ($first_part=="our-projects") {echo "active"; } else  {echo "noactive";}?>"><a href="#">Our Projects</a></li>
    <li class="<?php if ($first_part=="community") {echo "active"; } else  {echo "noactive";}?>"><a href="#">Community</a></li>
</ul>

<?php 
$directoryURI = $_SERVER['REQUEST_URI'];
$path = parse_url($directoryURI, PHP_URL_PATH);
$components = explode('/', $path);
$first_part = $components[1];
?>