<?php
$original = Array (
'id' => Array (
0 => 1,
1 => 3
),
'reward' => Array (
0 => 'Movie',
1 => 'Trip'
),
'cost' => Array (
0 => 50,
1 => 200
)
);
$output = array();
// Iterate the original array's [id] sub-array
foreach ($original['id'] as $idxkey => $newkey) {
// Add a sub-array using $newkey to the output array
$output[$newkey] = array(
// Using the index (not value), retrieve the corresponding reward
// value to use as the new array key
// and corresponding cost to use as the new subarray value
$original['reward'][$idxkey] => $original['cost'][$idxkey]
);
}
print_r($output);