- var_dump: documentation ( source)
- rtrim: documentation ( source)
- basename: documentation ( source)
- array_slice: documentation ( source)
- implode: documentation ( source)
- explode: documentation ( source)
<?php
$filenameOld = 'PX20170713_103320_2651093_00001';
var_dump(implode(array_slice(explode('_', rtrim(basename($filenameOld), ".xml" )), 0, 2)));