Array Multisort with a multidirectional array

Question

This one is baffling me at the moment, and I'm a little confused as to what it is doing.

So I have a multi directional array:

$h_info[69993] = array('price' => '1.00', 'url' => 'url', 'rating' => '4');
$h_info[85398] = array('price' => '3.00', 'url' => 'url', 'rating' => '2');
$h_info[34394] = array('price' => '9.00', 'url' => 'url', 'rating' => '0');

Now I have the following while loop

foreach ($h_info as $row) {
      foreach ($row as $key => $value){
        ${$key}[]  = $value; //Creates $price, $url... arrays.
      }  
    }
array_multisort($price, SORT_ASC, $h_info);

Now this works, but it removes the $h_info id from the array and outputs

Array
(
[0] => Array
    (
        [price] => 39
        [url] => url,
        [rating] => 4.5
    )
...

But i need the ID to stay - when I do this:

foreach ($h_info as $row => $id) {
      foreach ($row as $key => $value){
        ${$key}[]  = $value; //Creates $price, $url... arrays.
      }  
    }
array_multisort($price, SORT_ASC, $h_info);

The sort no longer works, but outputs the array correctly:

Array
(
[69993] => Array
    (
        [price] => 39
        [url] => url,
        [rating] => 4.5
    )
...

use usort() for multidimensional array hope this url will help you http://php.net/manual/en/function.usort.php — jilesh, Jan 20 '16 at 11:53
@jilesh That only seems to sort within the array? - I want to be able to go inside the array, get the price, and then sort it so the main id with the lowest price shows first — James Simpson, Jan 20 '16 at 12:10

score -1 · Accepted Answer · answered Jan 20 '16 at 12:11

Try this

$h_info[69993] = array('price' => '1.00', 'url' => 'url', 'rating' => '4');
$h_info[85398] = array('price' => '3.00', 'url' => 'url', 'rating' => '2');
$h_info[34394] = array('price' => '9.00', 'url' => 'url', 'rating' => '0');
//intitalize array
$result = array(); // or $result = [];
//add your main key into "key" parameter of array
array_walk($h_info, function (&$value,$key) use (&$result) {
    $arr_info = $value;
    $arr_info['key'] = $key;
    $result[] = $arr_info;

});
//sort in ascending order by price
usort($result, function($a, $b) {
    if($a['price']==$b['price']) return 0;
    return $b['price'] < $a['price']?1:-1; //  return $a['price'] < $b['price']?1:-1;(note : if you need it in descending order)
});

echo "<pre>";
print_r($result);
?>

and you will get result like this

    Array
(
    [0] => Array
        (
            [price] => 1.00
            [url] => url
            [rating] => 4
            [key] => 69993
        )

    [1] => Array
        (
            [price] => 3.00
            [url] => url
            [rating] => 2
            [key] => 85398
        )

    [2] => Array
        (
            [price] => 9.00
            [url] => url
            [rating] => 0
            [key] => 34394
        )

)

in ascending order by price if you need to know more information abouta array_walk() and usort() please check this links : http://php.net/manual/en/function.array-walk.php http://php.net/manual/en/function.usort.php

@jilesh - I need the outside (first array) to be the ID (699993, 85398...), and not just 0,1,2,3,4.... — James Simpson, Jan 20 '16 at 13:37
Although i could use array_search(699993, array_column($result, 'key')); — James Simpson, Jan 20 '16 at 13:53
@jilesh - Got it working using a bit of your example and a array_search to get the required results Thanks — James Simpson, Jan 20 '16 at 14:07
@James I really hope you had a look at the duplicate, because the solution is as simple as `uasort($h_info, function ($a, $b) { return $a['price'] - $b['price']; });` — deceze, Jan 20 '16 at 14:56
@deceze - I have just gone back through the usort example and modified my code, think it works slightly quicker than the way I was doing it, although that worked in the end too. Thanks for pointing me in the right direction. — James Simpson, Jan 20 '16 at 18:22

Array Multisort with a multidirectional array

1 Answers1