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<?php $a = [1,2,3]; $coverageList = [1=>0]; var_dump(array_flip($a)); var_dump($coverageList); var_dump(array_diff_key(array_flip($a), $coverageList)); ?>
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 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 - 8.1.30, 8.2.0 - 8.2.24, 8.3.0 - 8.3.12
array(3) { [1]=> int(0) [2]=> int(1) [3]=> int(2) } array(1) { [1]=> int(0) } array(2) { [2]=> int(1) [3]=> int(2) }

preferences:
64.67 ms | 408 KiB | 5 Q