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<?php $a = ['a' => ['1','2']]; $b = ['a' => ['3','4']]; var_dump(array_merge_recursive($a, $b)['a']); var_dump(($a + $b)['a']);
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 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(4) { [0]=> string(1) "1" [1]=> string(1) "2" [2]=> string(1) "3" [3]=> string(1) "4" } array(2) { [0]=> string(1) "1" [1]=> string(1) "2" }
Output for 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Parse error: syntax error, unexpected '[' in /in/j5l3d on line 8
Process exited with code 255.

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