// Separate name and extension of given file
$fullFileName = 'my.example.file.ext';
$fileExt  = substr($fullFileName, strrpos($fullFileName, '.') + 1);
$fileName = str_replace("." . $fileExt, "", $fullFileName);

/**
 * Results:
 *
 * $fileExt = ext
 * $fileName = my.example.file
 */