Filter and group data from a 2d array according to a 2d whitelist/mapping array

I'm trying to achieve proper merging of two 2d arrays.

$year = [
    ['name' => '2020'],
    ['name' => '2019'],
    ['name' => '2018'],
    ['name' => '2017']
];

$meeting = [
    ['name' => 'meeting1', 'year' => '2020'],
    ['name' => 'meeting2', 'year' => '2020'],
    ['name' => 'meeting3', 'year' => '2019'],
    ['name' => 'meeting4', 'year' => '2018'],
    ['name' => 'meeting5', 'year' => '2018'],
];

The result I desire would look like this:

[
    0 => [
        '2020' => [
            0 => ['name' => 'meeting1'],
            1 => ['name' => 'meeting2']
        ]
    ],
    1 => [
        '2019' => [
            0 => ['name' => 'meeting3']
        ]
    ],
    2 => [
        '2018' => [
            0 => ['name' => 'meeting4'],
            1 => ['name' => 'meeting5']
        ]
    ],
    3 => [
        '2017' => []
    ]
]

However both "+" operator and array_merge() used on $meeting and $year are producing different results than what I require. Is it possible to do using + operator or array_merge or am I required to use foreach loops?

There is no PHP native function for group array but as said, simple for loop should do it:

foreach($meeting as $e) {
    $array[$e['year']][] = array('name' => $e['name']);
}

And $array will you have you desire result.

Live example: 3v4l

Edit

If you want all the years from $year just init before as:

foreach($year as $e)
    $array[$e['name']] = [];

And then use the first for loop

So full solution will be:

foreach($year as $e)
    $array[$e['name']] = [];
foreach($meeting as $e)
    $array[$e['year']][] = array('name' => $e['name']);

Output:

array (
  2020 => 
  array (
    0 => 
    array (
      'name' => 'meeting1',
    ),
    1 => 
    array (
      'name' => 'meeting2',
    ),
  ),
  2019 => 
  array (
    0 => 
    array (
      'name' => 'meeting3',
    ),
  ),
  2018 => 
  array (
    0 => 
    array (
      'name' => 'meeting4',
    ),
    1 => 
    array (
      'name' => 'meeting5',
    ),
  ),
  2017 => 
  array (
  ),
)