请教php二维数组 查找相同的值合并 怎么写

请问php二维数组 查找相同的值合并 如何写？
这个是数组 
主要功能就是Thinkphp视图模型里查询的结果  我想

查询每个数组里的相同的标题值 然后进行合并                合并数组 貌似用array_merge()
我怎么查找相同的标题呢  foreach 遍历 返回数组里的索引值 可以么       貌似 key() 函数有这个功能 求好心人具体写个

相同的标题 数组元素的位置 这样返回 合并的时候就直接 这样的形式用 可以么
array_merge(array[0],array[1])

相同的标题 然后合并的是图片的连接字段这样 pictureurl就是这个不一样
简单说就是多图上传 发文章这样的  文章找找以后要是有几千篇 那数组就是好几倍的量  高效的计算 能用的 求大神指点啊~ 
这样

array(2) {
  [0] => array(5) {
    ["picTitle"] => string(33) "标题1"
    ["picCategroy"] => string(6) "分类"
    ["picAuthor"] => string(12) "作者"
    ["picPostTime"] => string(19) "2014-11-20 16:05:16"
    ["pictureurl"] => string(55) "attachment/picture/uploadify/20141120/546da0784831c.png"
  }
  [1] => array(5) {
    ["picTitle"] => string(33) "标题1"
    ["picCategroy"] => string(6) "分类"
    ["picAuthor"] => string(12) "作者"
    ["picPostTime"] => string(19) "2014-11-20 16:05:16"
    ["pictureurl"] => string(55) "attachment/picture/uploadify/20141120/546da0746edb8.png"
  }
}

------解决思路----------------------

$ar = array(
  array(
    "picTitle" => "标题1",
    "picCategroy" => "分类",
    "picAuthor" => "作者",
    "picPostTime" => "2014-11-20 16:05:16",
    "pictureurl" => "attachment/picture/uploadify/20141120/546da0784831c.png",
  ),
  array(
    "picTitle" => "标题1",
    "picCategroy" => "分类",
    "picAuthor" => "作者",
    "picPostTime" => "2014-11-20 16:05:16",
    "pictureurl" => "attachment/picture/uploadify/20141120/546da0746edb8.png",
  ),
);
foreach(call_user_func_array('array_merge_recursive', $ar) as $key=>$item) {
  $res[$key] = join(',', array_unique($item));
}
var_export($res);

array (
  'picTitle' => '标题1',
  'picCategroy' => '分类',
  'picAuthor' => '作者',
  'picPostTime' => '2014-11-20 16:05:16',
  'pictureurl' => 'attachment/picture/uploadify/20141120/546da0784831c.png,attachment/picture/uploadify/20141120/546da0746edb8.png',
)

------解决思路----------------------
随便写了下，没测试过，大楷是这么个思路

$ar = array(
  array(
    "picTitle" => "标题1",
    "picCategroy" => "分类",
    "picAuthor" => "作者",
    "picPostTime" => "2014-11-20 16:05:16",
    "pictureurl" => "attachment/picture/uploadify/20141120/546da0784831c.png",
  ),
  array(
    "picTitle" => "标题1",
    "picCategroy" => "分类",
    "picAuthor" => "作者",
    "picPostTime" => "2014-11-20 16:05:16",
    "pictureurl" => "attachment/picture/uploadify/20141120/546da0746edb8.png",
  ),
);

//标题=>数组索引数组
$map_arr=array();
foreach($ar as $key=>$item)
{
//判断是否在标题=>数组索引数组中
if(isset($map_arr[$item['picTitle']]))
{
//在的话合并
$ar[$key]=array_merge($ar[$key],$map_arr[$item['picTitle']]);
}
else
{
//不在的话存入映射索引
$map_arr[$item['picTitle']]=$item;
unset($ar[$key]); //删除原来在数组存在的值
}
}

------解决思路----------------------

$arr = array(
  array(
    "picTitle" => "标题1",
    "picCategroy" => "分类",
    "picAuthor" => "作者",
    "picPostTime" => "2014-11-20 16:05:16",
    "pictureurl" => "attachment/picture/uploadify/20141120/546da0784831c.png",
  ),
  array(
    "picTitle" => "标题1",
    "picCategroy" => "分类",
    "picAuthor" => "作者",
    "picPostTime" => "2014-11-20 16:05:16",
    "pictureurl" => "attachment/picture/uploadify/20141120/546da0746edb8.png",
  )
);
$item=array();
foreach($arr as $key=>$value){
    foreach($value as $k=>$v){
        if(!isset($item[$k])){
            $item[$k]=$v;
        }
    }
}
print_r($item);