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run code in 300+ PHP versions simultaneously
<?php $test = array(); $test['parent'] = array(); $test['parent']['child'] = 'foo'; $test['parent'][false] = 'bar'; $test['parent'][null] = 'baz'; var_dump($test);
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 - 5.6.40, 7.0.0 - 7.0.33, 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) { ["parent"]=> array(3) { ["child"]=> string(3) "foo" [0]=> string(3) "bar" [""]=> string(3) "baz" } }

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310.23 ms | 406 KiB | 457 Q