Online PHP editor | refs for KQ33q

<?php ## the user "class" class Foo { public int $id; public string $foo; public ?string $group = null; public function __construct(int $id, string $foo) { $this->id = $id; $this->foo = $foo; } } ## users db result $users_array = [ new Foo(999, 'abc'), new Foo(4, 'abc'), new Foo(5, 'xyz'), new Foo(8, 'xxx') ]; ## get IDs and build index $index = []; $ids = array_reduce($users_array, function(?array $ids, Foo $object) use(&$index) { $ids[] = $object->id; $index[$object->id] = $object; return $ids; }); ### Groups, fetched from SQL $groups = [ [ 'id' => 999, 'group' => 'group1'], [ 'id' => 8, 'group' => 'group2'], [ 'id' => 4, 'group' => 'group3'], ]; ### stiching foreach ($groups as $row) { $index[$row['id']]->group = $row['group']; } ## now the original array of users have their "group" property populated from the groups query var_dump($users_array);