convert date to reversed date

Is this a good way to convert 01/02/2007 to 20070201



$value='01/02/2007';

list($day, $month, $year) = split('[/.-]', $value);

$filename=$year.''.$month.''.$day;



It does work but i would like to verify if there are no better, more logical
ways to do this.

Thanks in advance