php 二维数组
array
(
[0] => array
(
[knowledge_id] => 1
[tag_id] => 2
)
[1] => array
(
[knowledge_id] => 1
[tag_id] => 3
)
)
把他里面量相同的[knowledge_id] => 1合并只留一个？？？？？？
回复讨论(解决方案) 留哪个呢？还是2个 tag_id 都要？
不用只要一个数组[0] => array
(
[knowledge_id] => 1
[tag_id] => 2
)
设原数组为 $ar, 则
$res = array(); //结果数组foreach($ar as $v) { if(! isset($res[$v['knowledge_id']])) $res[$v['knowledge_id']] = $v;}$res = array_values($res);