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<?php $array = [ [ ['plan' => 'basic'], ['plan' => 'small'], ['plan' => 'novice'], ['plan' => 'professional'], ['plan' => 'master'], ['plan' => 'promo'], ['plan' => 'newplan'] ] ]; // var_export($array); array_walk_recursive($array, function($leafvalue)use(&$flat1){$flat1[] = $leafvalue;}); var_export($flat1); echo "\n--or--\n"; var_export(array_column($array[0], 'plan')); echo "\n--or--\n"; foreach ($array[0] as $plans) { foreach ($plans as $value) { $flat2[] = $value; } } var_export($flat2); echo "\n--or--\n"; var_export(array_merge_recursive(...$array[0])['plan']);

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