Get latest file trailing number in php

Question

I have something like this in my directory:

slider-1.jpg
slider-2.png
slider-4.gif
slider-8.png
slider-11.gif

Now is there a way to get the last trailing number of "slider" images ? I need to get this so the next uploaded image should be named slider-12.xxx

I tried for each loop, but it obviously gets me slider-3 as a next name which is false in my case :)

ok, here is how I did it

foreach ($files as $filename) {
    $filesarr[]= $filename;
    $namearr = explode('.', $filename); //I had to grab this piece as well during the project, so this is main reason not usin Louis proposal.... i needed that array for something else...
    $numbers = explode('-', $namearr[1]);
    $compare[]=$numbers[2];   

}
sort($compare, SORT_NUMERIC); 
$assigned_number = end($compare) + 1;

Answer 1

You could try something like this:

$max = 0;
foreach($files AS $file) {
    $max = max($max, filter_var($file, FILTER_SANITIZE_NUMBER_INT));
}
$max++;

or this:

natcasesort($files);
$max = filter_var(array_slice($files, -1), FILTER_SANITIZE_NUMBER_INT) + 1;