Online PHP editor | refs for sPVfc

<?php $array = [ [ 'countries' => [ ['country_code' => 'US', 'growth' => 3.57], ['country_code' => 'CA', 'growth' => 4.77], ['country_code' => 'TT', 'growth' => 0], ], 'group_name' => 'North America', ], [ 'countries' => [ ['country_code' => 'BR', 'growth' => 2.19], ['country_code' => 'PE', 'growth' => 1.78], ['country_code' => 'UY', 'growth' => 8.83], ['country_code' => 'MX', 'growth' => 3.83], ], 'group_name' => 'South America', ], ]; var_export( array_map( function ($set) { usort($set['countries'], fn($a, $b) => $b['growth'] <=> $a['growth']); return $set; }, $array ) );