/*** 1,3,5,8,12 结果要求是2,2,3,4* 找规律 后面的数减去前一个**/public function arrayPendAction(){
    $arr = array(1,3,5,8,12);
    $count = count($arr)-1;
    foreach($arr as $k=>$val){
        if($k < $count) {
            $new[]= $arr[$k+1]-$arr[$k];
        }
    }
}