将字符串$pizza  = "a,b,c,d";变为$pizza  = "d,c,b,a";

$pizza  = "a,b,c,d";

$pieces = explode(",", $pizza);

$arr = array($pieces [3],$pieces [2],$pieces [1],$pieces [0]);

字符串转数组

$data ='ABCDJLSJDFLJ_IkkIkTw6_gQ2zvbyj_TEqRUUtL_JfmaaQjz';
$newdata = explode("_",$data);