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<?php $data = [[ "continent" => "Europa", "country" => "France", "capital" => "Paris", ],[ "continent" => "Europa", "country" => "Spain", "capital" => "Madrid", ],[ "continent" => "Asia", "country" => "Russia", "capital" => "Moscow", ]]; $groupByContinent = function(array $list) { return array_reduce($list, function($grouped, $item) { $grouped[$item['continent']][] = $item; return $grouped; }, []); }; $groupedByContinent = $groupByContinent($data); var_dump($groupedByContinent);
Output for 7.1.25 - 7.1.28, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(2) { ["Europa"]=> array(2) { [0]=> array(3) { ["continent"]=> string(6) "Europa" ["country"]=> string(6) "France" ["capital"]=> string(5) "Paris" } [1]=> array(3) { ["continent"]=> string(6) "Europa" ["country"]=> string(5) "Spain" ["capital"]=> string(6) "Madrid" } } ["Asia"]=> array(1) { [0]=> array(3) { ["continent"]=> string(4) "Asia" ["country"]=> string(6) "Russia" ["capital"]=> string(6) "Moscow" } } }

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