php将两个数组相同的key合并到一个数组

$arr = array(

    array(

    'id' => 1,

    'user_name'=>'test1'

    ),

    array(

    'id' => 2,

    'user_name'=>'test2'

    ),

    array(

    'id' => 3,

    'user_name'=>'test3'

    )

);

$arr2 = array(

     array(

    'id' => 1,

    'shop_name'=>'shop1'

    ),

    array(

    'id' => 5,

    'shop_name'=>'shop2'

    ),

    array(

    'id' => 3,

    'shop_name'=>'shop3'

    )

);

怎么根据2个数组id相同的一维数组，将$arr2的shop_name添加到$arr，如果没有相同的id，shop_name为空，形成如下数组：

$good_arr =array(

    array(

    'id' => 1,

    'user_name'=>'test1',

    'shop_name'=>'shop1'

    ),

    array(

    'id' => 2,

    'user_name'=>'test2',

    'shop_name'=>''

    ),

    array(

    'id' => 3,

    'user_name'=>'test3',

    'shop_name'=>'shop3'

    )

);

1. foreach($arr as $k2 =>&$v2) {

$v2['shop_name']='';

foreach($arr2 as $k =>$v) {

if($v2['id'] == $v['id']) {

$v2['shop_name'] = $v['shop_name'];

}

}

}

print_r($arr);

2. 

$tempArr = array();

foreach($arr2 as $item) 

    $tempArr[$item['id']] = $item['shop_name'];

foreach($arr as $k => $v) {

    if(array_key_exists($v['id'], $tempArr)) { 

        $arr[$k]['shop_name'] = $tempArr[$v['id']];

    } else {

        $arr[$k]['shop_name'] = '';

    }

}

$newArr = $arr;

3.

$tmp = '';

foreach ($arr2 as $k) { $tmp[$k['id']] = $k; }

foreach ($arr as &$v) {

    $sn = $tmp[$v['id']]['shop_name'];

    $sn = $sn ? $sn :'';

    $v['shop_name'] = $sn;

}

var_dump($arr);

?>

4.

$shop_name = array_column($arr2, 'shop_name', 'id');//方便减少foreach

foreach($arr as $key => $item) {

    $exist = array_key_exists($item['id'], $shop_name);

    $arr[$key]['shop_name'] = $exist ? $shop_name[$item['id']] : '';

}

print_r($arr);