Sort and shuffle multidimensional array

Question

I am working on gaming project, which needs sort and shuffle multidimensional array. First i need to sort based on bid. If multiple bids are same i need to sort based on priority. If bid & priority both are same means I need to shuffle those elements. For example we have 3 array elements in bid=0.4 & priority=4. Id's are 102,103 & 104. These array element position should be shuffled.

array(
    array('id' => 101, 'bid' => 0.5, 'priority' => 5),
    array('id' => 102, 'bid' => 0.4, 'priority' => 4),
    array('id' => 103, 'bid' => 0.4, 'priority' => 4),
    array('id' => 104, 'bid' => 0.4, 'priority' => 4),
    array('id' => 105, 'bid' => 0.3, 'priority' => 5),
    array('id' => 106, 'bid' => 0.3, 'priority' => 5),
    array('id' => 107, 'bid' => 0.2, 'priority' => 5),
    array('id' => 108, 'bid' => 0.7, 'priority' => 5),
    array('id' => 108, 'bid' => 0.1, 'priority' => 4)
);

check this answer http://stackoverflow.com/a/15003948/718224 may this help you. — Tony Stark, May 07 '13 at 08:09
In your example there is no place where bids with the same ID have same bid and priority — Baba, May 07 '13 at 08:11

score 4 · Answer 1 · answered May 07 '13 at 08:07

4

You should take a look at array_multisort to do that. There are examples on that page on how to sort a multi-dimensional array

<?php
// Obtain a list of columns
foreach ($data as $key => $row) {
  $bid[$key]  = $row['bid'];
  $prio[$key] = $row['priority'];
}

array_multisort($bid, SORT_ASC, $prio, SORT_ASC, $data);
?>

To shuffle I would add an extra column to the multidimensional array called "rand" and then fill it with a random number before you use multisort. Then you can add a 3th sort order on that column for shuffling.

answered May 07 '13 at 08:07

Hugo Delsing

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1

A simple usort is sufficient, for sorting at least. But I like your idea of adding a random number. – Salman A May 07 '13 at 08:12
1

Creating a function for sorting and using it isnt realy simpler then the above. A downvote because there is another option feels a little harsh. – Hugo Delsing May 07 '13 at 08:17
I did not downvote. But I am going to borrow your idea if you don't mind. – Salman A May 07 '13 at 08:18

score 2 · Accepted Answer · edited May 23 '17 at 11:55

Based on idea @Hugo's answer about using random weight:

$array = array(
    array('id' => 101, 'bid' => 0.5, 'priority' => 5),
    array('id' => 102, 'bid' => 0.4, 'priority' => 4),
    array('id' => 103, 'bid' => 0.4, 'priority' => 4),
    array('id' => 104, 'bid' => 0.4, 'priority' => 4),
    array('id' => 105, 'bid' => 0.3, 'priority' => 5),
    array('id' => 106, 'bid' => 0.3, 'priority' => 5),
    array('id' => 107, 'bid' => 0.2, 'priority' => 5),
    array('id' => 108, 'bid' => 0.7, 'priority' => 5),
    array('id' => 108, 'bid' => 0.1, 'priority' => 4)
);
function cmp(&$a, &$b) {                                     # notice the use of & in function signature
    if ($a['bid'] - $b['bid']) {
        return $a['bid'] - $b['bid'] > 0 ? 1 : -1;           # bid is different, sort using bid
    } else if ($a['priority'] - $b['priority']) {
        return $a['priority'] - $b['priority'] > 0 ? 1 : -1; # priority is different, sort using priority
    } else {
        if (isset($a['rw']) == false) {
            $a['rw'] = rand(1, 100);                         # assign random tie breaker
        } 
        if (isset($b['rw']) == false) {
            $b['rw'] = rand(1, 100);                         # assign random tie breaker
        } 
        if ($a['rw'] - $b['rw']) {
            return $a['rw'] - $b['rw'] > 0 ? 1 : -1;         # sort using random weight
        } else {
            return 0;
        }
    }
}
usort($array, 'cmp');
var_dump($array);

Output

array(9) {
[0]=>array(3) {["id"]=>int(108) ["bid"]=>float(0.1) ["priority"]=>int(4)}
[1]=>array(3) {["id"]=>int(107) ["bid"]=>float(0.2) ["priority"]=>int(5)}
[2]=>array(4) {["id"]=>int(106) ["bid"]=>float(0.3) ["priority"]=>int(5) ["rw"]=>int(70)}
[3]=>array(4) {["id"]=>int(105) ["bid"]=>float(0.3) ["priority"]=>int(5) ["rw"]=>int(73)}
[4]=>array(4) {["id"]=>int(103) ["bid"]=>float(0.4) ["priority"]=>int(4) ["rw"]=>int(29)}
[5]=>array(4) {["id"]=>int(104) ["bid"]=>float(0.4) ["priority"]=>int(4) ["rw"]=>int(67)}
[6]=>array(4) {["id"]=>int(102) ["bid"]=>float(0.4) ["priority"]=>int(4) ["rw"]=>int(80)}
[7]=>array(3) {["id"]=>int(101) ["bid"]=>float(0.5) ["priority"]=>int(5)}
[8]=>array(3) {["id"]=>int(108) ["bid"]=>float(0.7) ["priority"]=>int(5)}
}

score 1 · Answer 3 · answered May 07 '13 at 08:15

Usort would be ideal for this situation http://www.php.net/manual/en/function.usort.php
You define the function that does the comparisons

<?php
function cmp($a, $b)
{
    if ($a['bid'] == $b['bid']) {
        if ($a['priority'] == $b['priority']) return 0;
        return ($a['priority'] < $b['priority']) ? -1 : 1;
    }
    return ($a['bid'] < $b['bid']) ? -1 : 1;
}

usort($data, "cmp");
?>

Baba · Answer 4 · 2013-05-07T08:55:30.487

1

You can use usort

usort($array,function ($a, $b) {

            if ($a['id'] == $b['id']) {
                if ($a['priority'] == $b['priority'] && $a['bid'] == $b['bid']) {
                    $pos = array(-1,0,1);
                    return $pos[mt_rand(0, 2)]; // shurffle
                }

                $a = $a['priority'];
                $b = $b['priority'];

                return ($a == $b) ? 0 : (($a > $b) ? - 1 : 1); // sorty by priority
            }

            // First i need to sort based on bid
            $a = $a['id'];
            $b = $b['id'];
            return ($a == $b) ? 0 : (($a < $b) ? - 1 : 1); //sort by bid id
    });

edited May 07 '13 at 08:55

answered May 07 '13 at 08:16

Baba

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isnt the first check a typo? The `id` should be `bid` i guess? – Hugo Delsing May 07 '13 at 08:28
Its not .. its an if statement .. it would only run if `id` is the same if not it would use the id for sorting .... can be a little confusing but look at it one more time – Baba May 07 '13 at 08:42
I guess the comments you added threw me off. The comments mention `bid` while the code mentions `id` – Hugo Delsing May 07 '13 at 08:54

score 1 · Answer 5 · edited May 23 '17 at 10:24

Also based on @Hugos answer, adding shuffle using PHP built in shuffle() and range() functions:

<?php
$data=array(

array('id'=>101,'bid'=>0.5,'priority'=>5),
array('id'=>102,'bid'=>0.4,'priority'=>4),
array('id'=>103,'bid'=>0.4,'priority'=>4),
array('id'=>104,'bid'=>0.4,'priority'=>4),
array('id'=>105,'bid'=>0.3,'priority'=>5),
array('id'=>106,'bid'=>0.3,'priority'=>5),
array('id'=>107,'bid'=>0.2,'priority'=>5),
array('id'=>108,'bid'=>0.7,'priority'=>5),
array('id'=>108,'bid'=>0.1,'priority'=>4)
);


$rand=range(0,count($data)-1);
shuffle($rand);

foreach ($data as $key => $row) {
  $bid[$key]  = $row['bid'];
  $prio[$key] = $row['priority'];
}

array_multisort($bid, SORT_ASC, $prio, SORT_ASC, $rand, SORT_ASC, $data);

I first tried simply shuffling the array before sorting, but for some unknown reason, sorting seems to sort on id as well. Probably some effect of algorithm used.

score 0 · Answer 6 · answered Sep 27 '17 at 14:01

0

<?php

foreach ($data as $key => $row) {
  //just create a random field
  $data[$key]['randSort']= rand(1,999999);
  $sameRand[$key] = $data[$key]['randSort'];

  $bid[$key]  = $row['bid'];
  $prio[$key] = $row['priority'];
}

array_multisort($bid, SORT_ASC, $prio, SORT_ASC, $sameRand, SORT_ASC, $data);
?>

answered Sep 27 '17 at 14:01

Emile Lasan

1

It may helpful to others if you explain why your code is different and how it fixes the issue. – Dylan Slabbinck Sep 27 '17 at 14:22

score -1 · Answer 7 · answered May 07 '13 at 08:08

-1

put elements to be shuffled into an array and remove them from the initial array until the initial array is empty.
call shuffle on the created array
put the shuffled array into a new array with the results.

answered May 07 '13 at 08:08

Adder

5,708
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Sort and shuffle multidimensional array

7 Answers7