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$new<br /><br />$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 />$list = array(<br /> array('id' => 1, 'count' => 1),<br /> array('id' => 1, 'count' => 2),<br /> array('id' => 2, 'count' => 2),<br /> array('id' => 3, 'count' => 3),<br /> array('id' => 3, 'count' => 4)<br />);<br />$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 />
