3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = ['a' => 1]; $arr['b'] = &$arr['a']; var_dump($arr); $arr['b'] = 'xiami'; var_dump($arr);
Output for 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
array(2) { ["a"]=> &int(1) ["b"]=> &int(1) } array(2) { ["a"]=> &string(5) "xiami" ["b"]=> &string(5) "xiami" }
preferences:
103.82 ms | 1667 KiB | 4 Q