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<?php $arr = array ( 0 => array ( 0 => array ( 'userid' => '1610', ), 1 => array ( 'userid' => '1614', ), 2 => array ( 'userid' => '1616', ), ), 1 => array ( 0 => array ( 'userid' => '1610', ), 1 => array ( 'userid' => '1614', ), 2 => array ( 'userid' => '1616', ), 3 => array ( 'userid' => '1618', ), ), ); foreach($arr as $sub){ $res[][key($sub[0]) . "s"] = array_column($sub, 'userid'); } var_dump($res);
Output for 7.1.25 - 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 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14
array(2) { [0]=> array(1) { ["userids"]=> array(3) { [0]=> string(4) "1610" [1]=> string(4) "1614" [2]=> string(4) "1616" } } [1]=> array(1) { ["userids"]=> array(4) { [0]=> string(4) "1610" [1]=> string(4) "1614" [2]=> string(4) "1616" [3]=> string(4) "1618" } } }

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