3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a1 = [ "a" => 2, "b" => 0, "c" => 5, ]; $a2 = [ "a" => 3, "b" => 9, "c" => 7, "d" => 10, ]; $result = $a1; foreach ($a2 as $k => $v) { $result[$k] = ($result[$k] ?? 0) + $v; } var_export($result);
Output for 7.0.0 - 7.0.17, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
array ( 'a' => 5, 'b' => 9, 'c' => 12, 'd' => 10, )
Output for 5.4.12 - 5.4.45
Parse error: syntax error, unexpected '?' in /in/piO0q on line 18
Process exited with code 255.
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67.83 ms | 1002 KiB | 4 Q