[php] sort files by date in PHP

I currently have an index.php file which allows me to output the list of files inside the same directory, the output shows the names then I used filemtime() function to show the date when the file was modified. my problem now is, how will I sort the output to show the latest modified file ?, I've been thinking for awhile how to do this. if only I am doing it with mysql interaction there will be no problem at all. please show me an example how to sort and output the list of files starting from the latest modified one. this is what i have for now

if ($handle = opendir('.')) {
while (false !== ($file = readdir($handle))) {
       if ($file != "." && $file != "..") {
        $lastModified = date('F d Y, H:i:s',filemtime($file));
          if(strlen($file)-strpos($file,".swf")== 4){
            echo "<tr><td><input type=\"checkbox\" name=\"box[]\"></td><td><a href=\"$file\" target=\"_blank\">$file</a></td><td>$lastModified</td></tr>";
           }
       }
   }
   closedir($handle);
}

This would get all files in path/to/files with an .swf extension into an array and then sort that array by the file's mtime

$files = glob('path/to/files/*.swf');
usort($files, function($a, $b) {
    return filemtime($b) - filemtime($a);
});

The above uses an Lambda function and requires PHP 5.3. Prior to 5.3, you would do

usort($files, create_function('$a,$b', 'return filemtime($b)-filemtime($a);'));

If you don't want to use an anonymous function, you can just as well define the callback as a regular function and pass the function name to usort instead.

With the resulting array, you would then iterate over the files like this:

foreach($files as $file){
    printf('<tr><td><input type="checkbox" name="box[]"></td>
            <td><a href="%1$s" target="_blank">%1$s</a></td>
            <td>%2$s</td></tr>', 
            $file, // or basename($file) for just the filename w\out path
            date('F d Y, H:i:s', filemtime($file)));
}

Note that because you already called filemtime when sorting the files, there is no additional cost when calling it again in the foreach loop due to the stat cache.

$files = array_diff(scandir($dir,SCANDIR_SORT_DESCENDING), array('..', '.'));
print_r($files);

I use your exact proposed code with only some few additional lines. The idea is more or less the same of the one proposed by @elias, but in this solution there cannot be conflicts on the keys since each file in the directory has a different filename and so adding it to the key solves the conflicts. The first part of the key is the datetime string formatted in a manner such that I can lexicographically compare two of them.

if ($handle = opendir('.')) {
    $result = array();
    while (false !== ($file = readdir($handle))) {
        if ($file != "." && $file != "..") {
            $lastModified = date('F d Y, H:i:s',filemtime($file));
            if(strlen($file)-strpos($file,".swf")== 4){
                $result [date('Y-m-d H:i:s',filemtime($file)).$file] =
                    "<tr><td><input type=\"checkbox\" name=\"box[]\"></td><td><a href=\"$file\" target=\"_blank\">$file</a></td><td>$lastModified</td></tr>";
            }
        }
    }
    closedir($handle);
    krsort($result);
    echo implode('', $result);
}

An example that uses RecursiveDirectoryIterator class, it's a convenient way to iterate recursively over filesystem.

$output = array();
foreach( new RecursiveIteratorIterator( 
    new RecursiveDirectoryIterator( 'path', FilesystemIterator::SKIP_DOTS | FilesystemIterator::UNIX_PATHS ) ) as $value ) {      
        if ( $value->isFile() ) {
            $output[] = array( $value->getMTime(), $value->getRealPath() );
        }
}

usort ( $output, function( $a, $b ) {
    return $a[0] > $b[0];
});