wouldn't it make more sense to make a 3D array? like
$array[0]['stripNumber'] = ...
$array[0]['misc']=...
$array[0]['extension']=...
$array[0]['stripNumber'] = ...
$array[1]['misc']=...
$array[2]['extension']=...
to split up the filename --> that's quite easy.
PHP Code:
$filename = '03_09.jpg'; // in your script, you'll have the value set inside a loop
$misc=False;
list ($stripNumber, $extension) = explode ('.', $filename);
if (substr($stripNumber, -1) == 'M'){
$misc=True;
$stripNumber=substr($stripNumber, 0, -1);
}
$yourarray[] = array('misc'=>$misc, 'stripNumber'=>$stripNumber, 'extension'=>$extension);