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<?php $u = []; $a = [0, 1, 2, 0, 1, 2]; foreach ($a as $v) { if (isset($u[$v])) { continue; } $u[$v] = array_keys($a, $v); } var_dump($u);
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 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 - 8.3.7
array(3) { [0]=> array(2) { [0]=> int(0) [1]=> int(3) } [1]=> array(2) { [0]=> int(1) [1]=> int(4) } [2]=> array(2) { [0]=> int(2) [1]=> int(5) } }
preferences:
163.8 ms | 404 KiB | 172 Q