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run code in 300+ PHP versions simultaneously
<?php $a['a'] = array(3 => '123', 5 => '234'); $p = array(6 => '789', 9 => '876'); $a['a'] = $a['a'] + $p; var_dump($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, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.16 - 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) { ["a"]=> array(4) { [3]=> string(3) "123" [5]=> string(3) "234" [6]=> string(3) "789" [9]=> string(3) "876" } }

preferences:
269.75 ms | 406 KiB | 311 Q