3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = array('a' => 'A', 'b' => 'B', 'c' => 'C'); $b = array('a' => 'AA', 'd' => 'DD'); var_dump($a + $b); var_dump($b + $a); var_dump(array_merge($a, $b));
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 - 7.1.33, 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(4) { ["a"]=> string(1) "A" ["b"]=> string(1) "B" ["c"]=> string(1) "C" ["d"]=> string(2) "DD" } array(4) { ["a"]=> string(2) "AA" ["d"]=> string(2) "DD" ["b"]=> string(1) "B" ["c"]=> string(1) "C" } array(4) { ["a"]=> string(2) "AA" ["b"]=> string(1) "B" ["c"]=> string(1) "C" ["d"]=> string(2) "DD" }

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