<?php
$input = array (
"group_name_1" => "audi",
"group_locations_1" => "tokyo,barcelona,paris",
"group_quantities_at_locations_1" => "1,2,7",
"group_name_2" => "ford",
"group_locations_2" => "london,prag",
"group_quantities_at_locations_2" => "3,6"
);
$result = [];
array_walk(array_chunk($input,3),function($v)use(&$result){
$result[$v[0]] = array_combine(explode(",",$v[1]),explode(",",$v[2]));
});
print_r($result);
preferences:
50.94 ms | 402 KiB | 5 Q