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run code in 300+ PHP versions simultaneously
<?php $a = [ 'first' => 4, 'second' => 5, 'third' => 6 ]; $b = [ 'first' => 6, 'second' => 7, 'forth' => 8 ]; var_dump($a + $b);

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59.94 ms | 402 KiB | 5 Q