Order by date extracted from filename

Question

I am trying to order the result by year, the year extracted from the filename.

These are the N files in the folder I am scanning:

filename_2014.jpg
filename_2013.jpg
filename_2012.jpg
filename_2011.jpg
....
....

So I have wrote this function:

function Archivize() {
    $path = opendir('./');

    while($read = readdir($path)) {
            if($read != '.' && $read != '..') {
                $filename = current(explode(".", $read));
                $getYear = substr($filename, -4);
                ?>
                     <span class="year"><?php echo $getYear ?></span>
                <?php
            }
    }
     closedir($path);
}

It basically works, but I do not know how to order the results by the year extracted from the filename.

I read that the best way is to use an array and then sort(), but I really can't figure out how to apply this hint to my function.

function Archivize() {
    $path = opendir('./');

    $filesArray = array(); //just defining the array

    if ($handle = $path) {
        $loop = 1;
        while($read = readdir($path)) {
            if($read != '.' && $read != '..') {
                $filename = current(explode(".", $read));
                $getYear = substr($filename, -4);
                ?>
                    <span class="year"><?php echo $getYear ?></span>
                <?php
                echo "file:$read<br/>";
                $filesArray[] = $getYear;   //add the file into the files array
                $loop++;
            }
        }
            closedir($path);
    }
}

Probably the second function with the array is an aberration, but I am crawling in the dark.

UPDATE:

Actually the array is printed as:

filename_2011.jpg
filename_2012.jpg
filename_2013.jpg
filename_2014.jpg

I want to reverse it! Is it possible?

Answer 1

Have a look at the asort function and associative arrays. For your case, you'd want to Use the filename as the key, and your extracted year as the value.

Answer 2

you can store them in array and sort array using asort and print like this

function Archivize() {
    $path = opendir('./');

    $filesArray = array(); //just defining the array

    if ($handle = $path) {
        $loop = 1;
        while($read = readdir($path)) {
            if($read != '.' && $read != '..') {
                $filename = current(explode(".", $read));
                $getYear = substr($filename, -4);

                echo "file:$read<br/>";
                $filesArray[] = $getYear;   //add the file into the files array
                $loop++;
            }
        }

       asort($filesArray);
       foreach($filesArray as $n_year)
       {
       ?>
            <span class="year"><?php echo $n_year?></span><br/>
       <?php
       } 
            closedir($path);
    }
}

Answer 3

You will need 2 loops.

One for adding files to the array and another to write the contents to screen.

$path = opendir('./');
$list = array()
while($read = readdir($path)){
    if(substr($read, 0, 1) == '.')
        continue;

    $year = substr(basename($read, ".jpg"), -4);
    $list[$year] = $read;
}
closedir($path);

krsort($list); //using krsort to sort by keys (the years from most recent to older in this case)

foreach($list as $year => $filename){
    ?><span class="year"><?php echo $year ?></span><?php echo $filename;
}