$money =300;
$arr = array
( array
(
"period" => 1,
"money" => 100
),array
(
"period" => 2,
"money" => 90
),
array(
"period" => 3,
"money" => 50
),
);
//如何做到 $money 减去数组 money字段,规则是用上一个得到的值和下一个做比较
//比如 300100=200 再拿20090=110 再拿11050
//新手一枚 求大佬不吝赐教!!