实现排行版带有趋势的
实现排行版带有趋势的，该怎么实现呢？
------解决方案--------------------

//先变形为这样，即用 uid 做键。生成这些数据时就应该这样做好

$old_rank = array(

  132=>array('uid'=>132,'use_score'=>61570),

  121=>array('uid'=>121,'use_score'=>50932),

  145=>array('uid'=>145,'use_score'=>46789),

  100=>array('uid'=>100,'use_score'=>39089),

  167=>array('uid'=>167,'use_score'=>29089)

);

$new_rank = array(

  132=>array('uid'=>132,'use_score'=>61570),

  145=>array('uid'=>145,'use_score'=>51932),

  121=>array('uid'=>121,'use_score'=>50932),

  167=>array('uid'=>167,'use_score'=>40089),

  100=>array('uid'=>100,'use_score'=>39089)

);

foreach($new_rank as $k=>$v)

  $res[$k] = $v['use_score'] - $old_rank[$k]['use_score'];

print_r($res);

Array
(
    [132] => 0
    [145] => 5143
    [121] => 0
    [167] => 11000
    [100] => 0
)