php中foreach的一个有关问题

php中foreach的一个问题

<br />$list = array(<br />            array('id' => 1, 'count' => 1),<br />            array('id' => 1, 'count' => 2),<br />            array('id' => 2, 'count' => 2),<br />            array('id' => 3, 'count' => 3),<br />            array('id' => 3, 'count' => 4)<br />        );<br />        $sort = array();<br />        foreach($list as $v)<br />        {<br />            $sort[] = $v['id'];<br />        }<br />        $sort = array_unique($sort);<br />        $new = array();<br />        foreach($sort as $v1)<br />        {<br />            $c = 0;<br />            foreach($list as $v2)<br />            {<br />                if($v1 == $v2['id'])<br />                {<br />                    $c += $v2['count'];<br />                }<br />            }<br />            $new[] = array('id' => $v1, 'count' => $c);<br />        }<br /><br />这是现在的做法，求简单更合理的做法！！<br />需求：现有的数组：$list,需要得到的结果：把数组内重复的id对应的字段count合并。如上面的结果数组$new<br />

------解决思路----------------------

<br />$list = array(<br />            array('id' => 1, 'count' => 1),<br />            array('id' => 1, 'count' => 2),<br />            array('id' => 2, 'count' => 2),<br />            array('id' => 3, 'count' => 3),<br />            array('id' => 3, 'count' => 4)<br />        );<br /><br />// 執行計算操作<br />$tmp = array();<br /><br />foreach($list as $val){<br />    if(isset($tmp[$val['id']])){<br />        $tmp[$val['id']] += $val['count'];<br />    }else{<br />        $tmp[$val['id']] = $val['count'];<br />    }<br />}<br /><br />ksort($tmp); // 按key排序<br /><br />$new = array();<br />foreach($tmp as $k=>$v){<br />    array_push($new,array('id'=>$k,'count'=>$v));<br />}<br /><br />print_r($new);<br />

------解决思路----------------------

$list = array(<br />  array('id' => 1, 'count' => 1),<br />  array('id' => 1, 'count' => 2),<br />  array('id' => 2, 'count' => 2),<br />  array('id' => 3, 'count' => 3),<br />  array('id' => 3, 'count' => 4)<br />);<br />$new = array();<br />foreach($list as $r) {<br />  if(! isset($new[$r['id']])) $new[$r['id']] = $r;<br />  else $new[$r['id']]['count'] += $r['count'];<br />}<br />$new = array_values($new);<br />print_r($new);<br />

Array<br />(<br />    [0] => Array<br />        (<br />            [id] => 1<br />            [count] => 3<br />        )<br /><br />    [1] => Array<br />        (<br />            [id] => 2<br />            [count] => 2<br />        )<br /><br />    [2] => Array<br />        (<br />            [id] => 3<br />            [count] => 7<br />        )<br /><br />)<br />