Online PHP editor | refs for lNc1e

<?php $array = [ "SomeTitle" => [ 2018 => [ "February" => [], "January" => [], "March" => [] ], 2017 => [ "February" => [], "January" => [], "March" => [], "September" => [], "June" => [], "December" => [], "October" => [], "July" => [], "April" => [], "August" => [], "May" => [], ] ] ]; $lookup = array_flip( ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'] ); foreach ($array as &$years) { krsort($years); foreach ($years as &$months) { uksort($months, fn($a, $b) => $lookup[$a] <=> $lookup[$b]); } } var_export($array);