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<?php function subtract($a, $b) { $a2 = []; $lookup = array_count_values($b); foreach ($a as $v) { if ($lookup[$v] ?? 0) { $lookup[$v]--; } else { $a2[] = $v; } } return $a2; } var_dump(subtract( ['a', 'a', 'b', 'c', 'd', 'd', 'd', 'd'], ['a', 'b', 'd', 'd'] ));
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 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 - 8.3.7
array(4) { [0]=> string(1) "a" [1]=> string(1) "c" [2]=> string(1) "d" [3]=> string(1) "d" }
preferences:
154.27 ms | 403 KiB | 188 Q