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<?php $array = [ '1-2' => 'stuff', '3-4' => 'otherstuff', '2-1' => 'morestuff', '5-6' => 'evenmorestuff', '6-5' => 'evenmorestuffagain' ]; $result = array_unique(array_map(function ($key) { $parts = explode('-', $key); sort($parts); return implode('-', $parts); }, array_keys($array))); print_r($result);
Output for 5.6.38, 7.0.33, 7.1.25 - 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 - 8.1.30, 8.2.0 - 8.2.25, 8.3.0 - 8.3.13
Array ( [0] => 1-2 [1] => 3-4 [3] => 5-6 )
preferences:
79.56 ms | 407 KiB | 5 Q