3v4l.org

run code in 300+ PHP versions simultaneously
<?php header( 'Content-type: text/plain' ); $a = array(); $a['foo'][]['bar'] = 1; $a['foo'][]['bar'] = 2; var_dump($a);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(1) { ["foo"]=> array(2) { [0]=> array(1) { ["bar"]=> int(1) } [1]=> array(1) { ["bar"]=> int(2) } } }

preferences:
218.61 ms | 406 KiB | 385 Q