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<?php $prices = array ( '7.20', '7.40', '8.00', '8.50', '9.30', '10.40', '11.00', '12.00', '12.50', '13.00', ); //var_export(array_reduce($prices, fn($result, $v) => array_merge($result, [$v, $v]), [])); /* $result = []; foreach ($prices as $v) { [0 => $result[], 0 => $result[]] = [$v]; } var_export($result);*/ /*$result = []; foreach ($prices as $v) { array_push($result, $v, $v); } var_export($result);*/ //var_export(array_merge(...array_map(fn($e)=>[$e,$e],$prices))); //$r=[];foreach($prices as$v)array_push($r,$v,$v);var_export($r); var_export(array_merge(...array_map(null, $prices, $prices)));
Output for 8.0.1 - 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 ( 0 => '7.20', 1 => '7.20', 2 => '7.40', 3 => '7.40', 4 => '8.00', 5 => '8.00', 6 => '8.50', 7 => '8.50', 8 => '9.30', 9 => '9.30', 10 => '10.40', 11 => '10.40', 12 => '11.00', 13 => '11.00', 14 => '12.00', 15 => '12.00', 16 => '12.50', 17 => '12.50', 18 => '13.00', 19 => '13.00', )

preferences:
101.13 ms | 407 KiB | 5 Q