雙層foreach迴圈，取出key相等的元素，組成新數組返回，如何最佳化成一層迴圈？

if($arr1 && $arr2) {

        foreach($arr1 as $key1 => $val1) {            foreach($arr2 as $key2 => $val2) {                if($val1['orderId'] == $val2['orderId']) {                    $arr1[$key1]['transId'] = $val2['transId'];                }            }        }    }

回複內容：

if($arr1 && $arr2) {

        foreach($arr1 as $key1 => $val1) {            foreach($arr2 as $key2 => $val2) {                if($val1['orderId'] == $val2['orderId']) {                    $arr1[$key1]['transId'] = $val2['transId'];                }            }        }    }

if($arr1 && $arr2) {    $ids = array_column($arr2,'orderId');        foreach($arr1 as $key1 => $val1) {                       if(in_array($val1['orderId'] , $ids)) {                $arr1[$key1]['transId'] = $val1['orderId'];            }        }    }

$arr1 = array(    array(        'orderId' => 1,    ),    array(        'orderId' => 2,    ),    array(        'orderId' => 3,    ),    array(        'orderId' => 4,    ),    array(        'orderId' => 5,    ),    array(        'orderId' => 6,    ),);$arr2 = array(    array(        'orderId' => 2,        'transId' => 100001,    ),    array(        'orderId' => 4,        'transId' => 100002,    ),    array(        'orderId' => 5,        'transId' => 100003,    ),);if( $arr1 && $arr2) {    // `orderId` used for index    $index_key = 'orderId';    $column_key = 'transId';    $columns = array_column($arr2, $column_key, $index_key);    foreach($arr1 as &$val){        $_key = $val[$index_key];        if( array_key_exists($_key, $columns) ) {            $val[$column_key] = $columns[$_key];        }    }    print_r($arr1);}

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