Sorting sub array values in MultiDimension Array - php

Question

I am trying to sort an array sent from an XML feed.
The Array looks like this from print_r($answer);:
Array
(
[size] => Array
(
[0] => 1.5m x 1.5m
[1] => 1.5m x 3m
[2] => 3m x 6.0m
[3] => 3m x 2.3m
)
[rate] => Array
(
[0] => 80
[1] => 135
[2] => 295
[3] => 180
)
[sortorder] => Array
(
[0] => 3
[1] => 4
[2] => 1
[3] => 2
)
.
.
.
)
I want to get out the array:
Array
(
[size] => Array
(
[0] => 3m x 6.0
[1] => 3m x 2.3m
[2] => 1.5m x 1.5m
[3] => 1.5m x 3m
)
[rate] => Array
(
[0] => 295
[1] => 180
[2] => 80
[3] => 135
)
[sortorder] => Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
)
.
.
.
)
What I am trying to do is use the Sort Order sub array to display the items in that order
I have tried a number of uasort() and array_multisort() examples, but all seem to order the sub arrays and not the values inside the sub arrays
Any ideas will be a great help. Cheers

Answer 1

This one sorts $answer['sortorder'] and uses those keys to sort the rest of $answer without restructuring first.
// sort $answer['sortorder'] and retrieve indices.
asort($answer['sortorder']);
$idx = array_keys($answer['sortorder']);
// do sorting
$sorted = array();
foreach($answer as $key=>$subarr) {
if ($key != 'sortorder') { // don't sort
foreach($idx as $i) {
$sorted[$key][] = $subarr[$i];
}
} else {
// $answer['sortorder'] is already sorted.
$sorted[$key] = $subarr;
}
}
print_r($sorted);
See it in action here.

Answer 2

This approach will re-structure the array with the sort order being the index, sort the array, then return it to it's original structure.
echo '<pre>';
$array['size'][0] = '1.5m x 1.5m';
$array['size'][1] = '1.5m x 3m';
$array['size'][2] = '3m x 6.0m';
$array['size'][3] = '3m x 2.3m';
$array['rate'][0] = 80;
$array['rate'][1] = 135;
$array['rate'][2] = 295;
$array['rate'][3] = 180;
$array['sortorder'][0] = 3;
$array['sortorder'][1] = 4;
$array['sortorder'][2] = 1;
$array['sortorder'][3] = 2;
$temp = array();
foreach($array['sortorder'] as $key => $value)
{
$temp[$array['sortorder'][$key]] = array(
'size'=>$array['size'][$key],
'rate'=>$array['rate'][$key],
'sortorder'=>$array['sortorder'][$key]
);
}
ksort($temp);
$array = array();
foreach($temp as $key => $value)
{
$array['size'][] = $value['size'];
$array['rate'][] = $value['rate'];
$array['sortorder'][] = $value['sortorder'];
}
print_r($array);

Answer 3

May I propose to use a different array structure that bundles each size, rate and sort order into one item:
array(
array('size' => '...', 'rate' => '...', 'sort order' => '...'),
...
)
That makes it trivial to sort, and in fact easier to work with in general.
This PHP 5.3+ code does this transformation and sorting:
$answer = array_map(function ($size, $rate, $sortorder) {
return compact('size', 'rate', 'sortorder');
}, $answer);
usort($answer, function ($a, $b) { return $a['sortorder'] - $b['sortorder']; });