问个PHP数组合并的有关问题~请

问个PHP数组合并的问题~请高手指点

$arr1=array(<br>            "0"=>array(<br>                'id' => '2',<br>                'b' => 0,<br>                'num' => 4<br><br>                ),<br><br>            "1"=>array(<br>                'id' => '1',<br>                'b' => 0,<br>                'num' => 4 <br>                )<br>        );<br>        $arr2=array(<br>            "1"=>array(<br>                'id' => '3',<br>                'b' => 0,<br>                'num' => 4<br><br>                ),<br><br>            "2"=>array(<br>                'id' => '2',<br>                'b' => 0,<br>                'num' => 4 <br>                )<br>        );

想要合并这个两个数组，判断条件，id,b两个元素都相同的情况的NUM值相加。新数组键值重新排列0 1 2 3
求高手指点。谢谢。
------解决思路----------------------

$arr1=array(<br>            "0"=>array(<br>                'id' => '2',<br>                'b' => 0,<br>                'num' => 4<br> <br>                ),<br> <br>            "1"=>array(<br>                'id' => '1',<br>                'b' => 0,<br>                'num' => 4 <br>                )<br>        );<br> $arr2=array(<br>            "1"=>array(<br>                'id' => '3',<br>                'b' => 0,<br>                'num' => 4<br> <br>                ),<br> <br>            "2"=>array(<br>                'id' => '2',<br>                'b' => 0,<br>                'num' => 4 <br>                )<br>        );<br>foreach($arr1 as $v) $res["$v[id]_$v[b]"] = $v;<br>foreach($arr2 as $v)<br>  if(isset($res["$v[id]_$v[b]"])) $res["$v[id]_$v[b]"]['num'] += $v['num'];<br>  else $res["$v[id]_$v[b]"] = $v;<br>print_r(array_values($res));

Array<br>(<br>    [0] => Array<br>        (<br>            [id] => 2<br>            [b] => 0<br>            [num] => 8<br>        )<br><br>    [1] => Array<br>        (<br>            [id] => 1<br>            [b] => 0<br>            [num] => 4<br>        )<br><br>    [2] => Array<br>        (<br>            [id] => 3<br>            [b] => 0<br>            [num] => 4<br>        )<br><br>)<br><br>

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