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run code in 300+ PHP versions simultaneously
<?php $first = [ '01-1970' => 0.00, '03-2019' => 4350.00, '05-2019' => 150.00, '06-2019' => 50.00, ]; $second = [ '03-2019' => 0.00, '04-2019' => 0.00, '06-2019' => 34.83, ]; $result = $first; foreach ($second as $k => $v) { $result[$k] = ($result[$k] ?? 0) + $v; } uksort( $result, fn($a, $b) => preg_replace('/(\d+)-(\d+)/', '$2-$1', $a) <=> preg_replace('/(\d+)-(\d+)/', '$2-$1', $b) ); var_export($result);
Output for 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
array ( '01-1970' => 0.0, '03-2019' => 4350.0, '04-2019' => 0.0, '05-2019' => 150.0, '06-2019' => 84.83, )

preferences:
79.19 ms | 402 KiB | 62 Q