I would just use preg_split to split the string into several variables and put them into an array, if you must.
$str = 'path/to/input-180x129.png';
// get info of a path
$pathinfo = pathinfo($str);
$filename = $pathinfo['basename'];
// regex to split on "-", "x" or "."
$format = '/[\-x\.]/';
// put them into variables
list($name, $width, $height, $format) = preg_split($format, $filename);
// put them into an array, if you must
$array = array(
'name' => $name,
'width' => $width,
'height' => $height,
'format' => $format
);
After Esailija's great comment I've made new code that should work better!
We simply get all matches from a preg_match
and do pretty much the same we did on previous code.
$str = 'path/to/input-180x129.png';
// get info of a path
$pathinfo = pathinfo($str);
$filename = $pathinfo['basename'];
// regex to match filename
$format = '/(.+?)-([0-9]+)x([0-9]+)\.([a-z]+)/';
// find matches
preg_match($format, $filename, $matches);
// list array to variables
list(, $name, $width, $height, $format) = $matches;
// ^ that's on purpose! the first match is the filename entirely
// put into the array
$array = array(
'name' => $name,
'width' => $width,
'height' => $height,
'format' => $format
);