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<?php $arr = [[14], [], [12,14]]; $res = call_user_func_array('array_merge', $arr); print_r(array_unique($res));
Output for 7.1.0 - 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 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
Array ( [0] => 14 [1] => 12 )
preferences:
146.67 ms | 403 KiB | 213 Q