Online PHP editor | refs for k3d4T

<?php $a = Array ( 'piata-fortei-munca' => Array ( '0' => Array ( 'date' => '2019-10-19 09:10:07', 'user' => '61006cd2ac1728c3c08c2e8d9d714a81', 'slug' => 'piata-fortei-munca' ), '1' => Array ( 'date' => '2019-10-19 09:10:07', 'user' => '61006cd2ac1728c3c08c2e8d9d714a81', 'slug' => 'piata-fortei-munca' ), '2' => Array ( 'date' => '2019-10-19 09:10:09', 'user' => 'a8b6c2879aa0f38da1fd49a4e86e1525', 'slug' => 'piata-fortei-munca' ), '3' => Array ( 'date' => '2019-10-19 09:10:09', 'user' => 'a8b6c2879aa0f38da1fd49a4e86e1525', 'slug' => 'piata-fortei-munca' ), '4' => Array ( 'date' => '2019-10-19 09:10:18', 'user' => '42d80d8dc9a9547223e2bfea172738cf', 'slug' => 'piata-fortei-munca' ) ), 'blockchain-bitcoin' => Array ( '0' => Array ( 'date' => '2019-10-19 08:10:58', 'user' => '4b01473f1d3f1846b1e83b33e1af0b11', 'slug' => 'blockchain-bitcoin' ), '1' => Array ( 'date' => '2019-10-19 08:10:58', 'user' => '4b01473f1d3f1846b1e83b33e1af0b11', 'slug' => 'blockchain-bitcoin' ) ) ); array_walk($a, function(&$v ,$k){ $v = array_values(array_column($v, null, 'user')); }); print_r($a);