删除与另一个多维数组共享一个键-值对的子数组

Question

I have 2 arrays as below. I want to remove data from array2 if array1 has the stu_id . final array should be like result_array .

$array1 = Array
(
    [0] => Array
        (
            [stu_id] => 1
            [name] => mr.a
        )
    [1] => Array
        (
            [stu_id] => 3
            [name] => mr.b
        )
)

$array2 = Array
(
    [0] => Array
        (
            [id] => 1
            [stu_id] => 1
            [data] => abc
        )
    [1] => Array
        (
            [id] => 2
            [stu_id] => 2
            [data] => xyz
        )
    [3] => Array
        (
            [id] => 3
            [stu_id] => 3
            [data] => aaa
        )
)

$result_array = Array
(
    [0] => Array
        (
            [id] => 2
            [stu_id] => 2
            [data] => xyz
        )
)

I tried array_diff, $result_array = array_diff($array2, $array1); but it's not working.

Please help me to do this.

Answer 1

Temporarily assign keys using array_column() with stud_id ( NULL retains the full subarray data), then use array_diff_key() to filter, and array_values() to reset the keys:

Code: ( Demo )

$array1=[
    ['stu_id'=>1,'name'=>'mr.a'],
    ['stu_id'=>3,'name'=>'mr.b']
];

$array2=[
    ['id'=>1,'stu_id'=>1,'data'=>'abc'],
    ['id'=>2,'stu_id'=>2,'data'=>'xyz'],
    ['id'=>3,'stu_id'=>3,'data'=>'aaa']
];

//var_export(array_column($array1,NULL,'stu_id'));
//var_export(array_column($array2,NULL,'stu_id'));
var_export(array_values(array_diff_key(array_column($array2,NULL,'stu_id'),array_column($array1,NULL,'stu_id'))));

Output:

array (
  0 => 
  array (
    'id' => 2,
    'stu_id' => 2,
    'data' => 'xyz',
  ),
)

---

If you'd like to use a foreach loop structure, generate a filtering array of stu_id 's from $array1 and write a conditional check on each iteration of $array2 . This method doesn't not modify the original arrays, so they can be reused "down script".

Code:

$stu_ids=array_column($array1,'stu_id');
foreach($array2 as $row){
    if(!in_array($row['stu_id'],$stu_ids)){
        $result[]=$row;  // auto-index the qualifying subarrays
    }
}
var_export($result);
// same result as above method

Answer 2

foreach($array1 as $data1){
    foreach($array2 as $k => $data2){
        if($data2["stu_id"] == $data1["stu_id"]){
            unset($array2[$k]);
            break;
        }
    }
}
$result_array = $array2;