3v4l.org

run code in 300+ PHP versions simultaneously
<?php function array_not_unique(array $a): array { return array_diff_key( $a, array_unique($a) ); } $array = [ 'apple', 'orange', 'pear', 'banana', 'apple', 'pear', 'kiwi', 'kiwi', 'kiwi' ]; var_export(array_not_unique($array));
Output for 7.4.5, 8.0.1 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.28, 8.4.1 - 8.4.15, 8.5.0
array ( 4 => 'apple', 5 => 'pear', 7 => 'kiwi', 8 => 'kiwi', )
preferences:
105.46 ms | 406 KiB | 5 Q