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run code in 150+ php & hhvm versions
Bugs & Features
<?php $a = array(23 => 'a1', 108 => 'a2', 45 => 'a3'); $b = array(18 => 'b1', 30 => 'b2', 100 => 'b3'); var_dump($a+$b); var_dump($b+$a);
Output for 4.3.0 - 7.1.0
array(6) { [23]=> string(2) "a1" [108]=> string(2) "a2" [45]=> string(2) "a3" [18]=> string(2) "b1" [30]=> string(2) "b2" [100]=> string(2) "b3" } array(6) { [18]=> string(2) "b1" [30]=> string(2) "b2" [100]=> string(2) "b3" [23]=> string(2) "a1" [108]=> string(2) "a2" [45]=> string(2) "a3" }