3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [ 'visitPoints'=>[ 20=>[2,5,6,8,10,11], 35=>[2,5,6], 57=>[1] ], 'islands'=>[ 20=>[5,10,11], 35=>[5,6] ], 'animals'=>[ 20=>[5,11], 35=>[] ] ]; $result = [ 20=>[5,11], 35=>[], 57=>[] ]; print_r($result);
Output for 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
Array ( [20] => Array ( [0] => 5 [1] => 11 ) [35] => Array ( ) [57] => Array ( ) )
preferences:
65.62 ms | 406 KiB | 5 Q