按键排序多维数组的值

Question

table

cat_id | cat_parent_id | cat_name   
---------------------------------
12     |      0        |  Car    
13     |      0        |  Manga      
14     |      12       |  Volvo      
15     |      12       |  Mercedes-Benz      
16     |      13       |  Naruto     
17     |      13       |  Hunter X Hunter
18     |      0        |  Animals

Im trying to get the categories in the db and put it in an array then after use that array to build the code for the drop down list. Here is the code BELOW.

while($row = dbFetchArray($result)) {
        list($id, $parentId, $name) = $row;

        if ($parentId == 0) {
            // we create a new array for each top level categories
            $categories[$id] = array('id' => $id, 'name' => $name, 'children' => array());
        } else {
            // the child categories are put int the parent category's array
            $categories[$parentId]['children'][] = array('id' => $id, 'name' => $name); 
        }
}

$list = '';
    foreach ($categories as $key => $value) {
        $name     =  "--" . strtoupper($value['name']) . "--";
        $children = $value['children'];

        $list .="<option value=\"{$value['id']}\"";
        if ($value['id'] == $catId) {
                $list.= " selected";
        }
        $list .= ">$name</option>\r\n";


        foreach ($children as $child) {
            $list .= "<option value=\"{$child['id']}\"";
            if ($child['id'] == $catId) {
                $list.= " selected";
            }

            $list .= ">{$child['name']}</option>\r\n";
        }


    }

final value of $categories array

Array
(
    [12] => Array
        (
            [id] => 12
            [name] => Car
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 14
                            [name] => Volvo
                        )

                    [1] => Array
                        (
                            [id] => 15
                            [name] => Mercedez-Benz
                        )

                )

        )

    [13] => Array
        (
            [id] => 13
            [name] => Manga
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 16
                            [name] => Naruto
                        )

                    [1] => Array
                        (
                            [id] => 17
                            [name] => Hunter X Hunter
                        )

                )

        )

    [18] => Array
        (
            [id] => 18
            [name] => Animals
            [children] => Array
                (
                )

        )

)

But I want to sort the $categories by the value of the key 'name'.

I tried many times and so far this is my solution.

function sortByName($a, $b) {
    return strcmp($a["name"], $b["name"]);
}

usort($categories,"sortByName");

foreach($categories as $k => $v){
    foreach($v as $kk => $vv) {

        if ($kk == "children") {
            usort($vv,"sortByName");

            print_r($vv );

        }
    }
}

My problem is even that the first level key 'name' sorts fine, but my solution to sort the second level didnt work.

And also when the sorting happens the index of the array i sorted become 0 1 2 3.

like for example when i sort this by the value of the key 'name' 18 12 13 will become 0 1 2

Array(
    [18] => Array
        (
            [id] => 18
            [name] => aa


        )

    [12] => Array
        (
            [id] => 12
            [name] => Car


        )

    [13] => Array
        (
            [id] => 13
            [name] => Manga


        )            
)

how can i sort but I also want 18 12 13 not change?

so I want my $categories array to be this

Array
(

    [18] => Array
        (
            [id] => 18
            [name] => Animals
            [children] => Array
                (
                )

        )

    [12] => Array
        (
            [id] => 12
            [name] => Car
            [children] => Array
                (
            [0] => Array
                        (
                            [id] => 15
                            [name] => Mercedes-Benz
                        )

                    [1] => Array
                        (
                            [id] => 14
                            [name] => Volvo
                        )

            )

        )

    [13] => Array
        (
            [id] => 13
            [name] => Manga
            [children] => Array
                (
            [0] => Array
                        (
                            [id] => 17
                            [name] => Hunter X Hunter
                        )

                    [1] => Array
                        (
                            [id] => 16
                            [name] => Naruto
                        )

                )

        )
)

Answer 1

Too much effort. Use NAME as array KEY and then sort by key wit ksort

Answer 2

I think the issue is that PHP doesn't interpret those numerical indexes as being keys, just indices, so that it doesn't retain them after the sort. If you convert them to strings and then do the sort, I suspect it will keep them. Alternatively, you could swap the numerical keys with your names (if names are unique, of course), do a simple ksort (as suggested in previous answers), and then swap them back afterwards.

Answer 3

you an use uksort to perform what you want. But there is something wrong in your design.

Like @Lukasz Kujawa said, php arrays are designed to be accessed in O(1). Your design, as C arrays, force everything to be O(n) and to add a step in the process.

I will give you the "solution" with uksort but to me it is not something good to do.

uksort($categories,function($a,$b)use($categories){
       return return strcmp($categories[$a]["name"], $categories[$b]["name"]);
}