php SPL iterator practice

iterator.php

<?php
$project_dir = '/opt/lampp/htdocs/parixan/data';
$RealPath = realpath($project_dir);
var_dump($RealPath);

$Directory = new RecursiveDirectoryIterator($RealPath, FilesystemIterator::SKIP_DOTS | FilesystemIterator::CURRENT_AS_FILEINFO);
foreach ($Directory as $dir) {
    if( $Directory->hasChildren() ) {
        $ch = $Directory->getChildren();
        // var_dump($ch->key());
        $fsi = new RecursiveIteratorIterator($ch, FilesystemIterator::SKIP_DOTS | RecursiveIteratorIterator::LEAVES_ONLY );
        $fsi_ = iterator_to_array($fsi, true);
        // var_dump($fsi_);
        krsort($fsi_);
        var_dump($fsi_);
        foreach ($fsi_ as $f) {
            var_dump($f->getFileName());
            if($f->isDir()) {
                $fi = new RecursiveDirectoryIterator($f, FilesystemIterator::SKIP_DOTS | FilesystemIterator::CURRENT_AS_FILEINFO);
                $It = new RecursiveIteratorIterator($fi);
                $Regex = new RegexIterator($It, '#/thumbnails/.*#i', RecursiveRegexIterator::GET_MATCH);
                $th = iterator_to_array($Regex);
                krsort($th);
                var_dump($th);
                foreach($th as $v){
                     var_dump($v);
                }
                // var_dump(__LINE__,iterator_to_array($fi));
            }
        }
    }

}
exit;
$files_ = iterator_to_array($Directory, true);
// var_dump($files_);
// // exit;

// exit;
// foreach ($files_ as $file) {
//     $fsi = new RecursiveDirectoryIterator($file,
//                 FilesystemIterator::CURRENT_AS_FILEINFO | FilesystemIterator::SKIP_DOTS );
//     $fsi_ = iterator_to_array($fsi, true);
//     krsort($fsi_);
//     var_dump($fsi_);
//     foreach ($fsi_ as $f) {
//         if($f->isDir()){
//             // $d = scandir($f->getPathname(),1);
//             // var_dump($d);
//             $th = new RecursiveDirectoryIterator($f->getPathname().DS.'thumbnails', FilesystemIterator::SKIP_DOTS | FilesystemIterator::CURRENT_AS_FILEINFO);
//             var_dump($th);
//             // $fd_ = iterator_to_array($fd,true);
//             // krsort($fd_);
//             // var_dump($fd_);
//             $format = "<br/> Directory : %s , Created at : %s , Modified at : %s<hr/>";
//             printf($format, $f->getPathname(), $f->getCtime(), $f->getMtime());
//         }
//     }
// }