3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [ 'uid_1' => [ 'sub_1' => [ 'sub_sub_1' => ['id1' => 'val_1', 'id2' => 'val_2'] ], 'sub_2' => [ 'sub_sub_1' => ['id1' => 'val_1', 'id2' => 'val_2'], 'sub_sub_2' => ['id3' => 'val_3', 'id4' => 'val_4'] ] ], 'uid_2' => [ 'sub_1' => [ 'sub_sub_1' => ['id1' => 'val_1', 'id3' => 'val_3'] ], ] ]; foreach ($array as &$uids) { foreach ($uids as &$subs) { $subs['sub_sub_1']['id5'] = 'val_5'; } } var_export($array);
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.13
array ( 'uid_1' => array ( 'sub_1' => array ( 'sub_sub_1' => array ( 'id1' => 'val_1', 'id2' => 'val_2', 'id5' => 'val_5', ), ), 'sub_2' => array ( 'sub_sub_1' => array ( 'id1' => 'val_1', 'id2' => 'val_2', 'id5' => 'val_5', ), 'sub_sub_2' => array ( 'id3' => 'val_3', 'id4' => 'val_4', ), ), ), 'uid_2' => array ( 'sub_1' => array ( 'sub_sub_1' => array ( 'id1' => 'val_1', 'id3' => 'val_3', 'id5' => 'val_5', ), ), ), )

preferences:
78.18 ms | 408 KiB | 5 Q