Sorting multidimensional number array in PHP - php

Question

I have issues sorting an multidimensional array.
The array looks like:
$array = array(
array("token" => array(100, 240, 348, 23, 17),
array("token" => array(293, 28, 283, 2, 28),
array("token" => array(842, 23, 72, 98, 114)
);
Now I want to sort them by "column". That means, the first column of numbers (100, 293, 842) must be sorted, then the second column (but keeping the first column as it is! It may happen that the columns have the same number with multiple rows) and so on.
Actually I tried this to do with usort(), but this will work only when sorting the first column:
function do_sort($a, $b) {
$tok_a = $a["token"];
$tok_b = $b["token"];
if ($tok_a[0] <= $tok_b[0])
return false;
else
return true;
}
usort($array, "do_sort");
How can I do this? Thanks

Answer 1

Here's possible solution:
get rid of 'token', i.e., make 2D array
swap columns and rows (transpose array)
sort each column
swap back columns and rows (get initial structure)
put 'token' back
Code:
function array_transpose(array $array) {
$result = array();
foreach ( $array as $rowNum => $row ) {
foreach ( $row as $colNum => $value ) {
$result[$colNum][$rowNum] = $value;
}
}
return $result;
}
$array = array(
array("token" => array(100, 240, 348, 23, 17)),
array("token" => array(293, 28, 283, 2, 28)),
array("token" => array(842, 23, 72, 98, 114)),
);
// get rid of 'token'
foreach ( $array as &$item ) {
$item = $item['token'];
}
unset($item);
// swap columns and rows
$array = array_transpose($array);
// sort columns
foreach ( $array as &$item ) {
sort($item);
}
unset($item);
// swap back columns and rows
$array = array_transpose($array);
// put 'token' back
foreach ( $array as &$item ) {
$item = array('token' => $item);
}
unset($item);
// display results
foreach ( $array as $row ) {
foreach ( $row['token'] as $value ) {
printf('%-7d', $value);
}
echo "\n";
}
Output:
100 23 72 2 17
293 28 283 23 28
842 240 348 98 114

Answer 2

I think this will do what you are after. I've made some assumptions here (such as $array is really an array, has at least one sub-array, all sub-arrays have token as the key, and all sub-arrays have the same number of elements).
<?php
$array = array(
array("token" => array(100, 240, 348, 23, 17)),
array("token" => array(293, 28, 283, 2, 28)),
array("token" => array(842, 23, 72, 98, 114)),
);
$count_outer = count($array);
$count_inner = count($array[0]['token']);
for ($i=0; $i < $count_inner; $i++) {
$temp_arr = array();
for ($j=0; $j < $count_outer; $j++) {
$temp_arr[] = $array[$j]['token'][$i];
}
sort($temp_arr);
for ($j=0; $j < $count_outer; $j++) {
$array[$j]['token'][$i] = $temp_arr[$j];
}
}
foreach ($array as $value) {
var_dump($value);
echo '<br>';
}
Output:
array(1) { ["token"]=> array(5) {
[0]=> int(100) [1]=> int(23) [2]=>
int(72) [3]=> int(2) [4]=> int(17) } }
array(1) { ["token"]=> array(5) {
[0]=> int(293) [1]=> int(28) [2]=>
int(283) [3]=> int(23) [4]=> int(28) }
} array(1) { ["token"]=> array(5) {
[0]=> int(842) [1]=> int(240) [2]=>
int(348) [3]=> int(98) [4]=> int(114)
} }

Answer 3

Can't you just
foreach ($array as &$item) {
sort($item['token']);
}
Or have I misunderstood the question?