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<?php // No initialisation of $optionsbyuser or sub-arrays! $optionsbyuser[1][] = 2; $optionsbyuser[1][] = 3; print_r($optionsbyuser);
Output for 5.6.0 - 5.6.23, 7.0.0 - 7.0.20, 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 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
Array ( [1] => Array ( [0] => 2 [1] => 3 ) )

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146.62 ms | 403 KiB | 206 Q