PHP二维数组去除重复，重复值相加

$arr = array(
array('id' => 122, 'name' => '张三', 'amount' => '1'),
array('id' => 123, 'name' => '李四', 'amount' => '1'),
array('id' => 124, 'name' => '王五', 'amount' => '1'),
array('id' => 125, 'name' => '赵六', 'amount' => '1'),
array('id' => 126, 'name' => '赵六', 'amount' => '2'),
array('id' => 126, 'name' => '赵六', 'amount' => '2')
);

$new = array();

foreach($arr as $row){
if(isset($new[$row['name']])){
$new[$row['name']]['amount'] += $row['amount'];
}else{
$new[$row['name']] = $row;
}
}

var_dump($new);