PHP/MySQL: Recreate multidimensional array from existing array

Question

I've got an multi-array (currently with objects) that I want to reorder based on a specific key/value.

Array
(
[0] => stdClass Object
    (
        [task_id] => 1
        [task_title] => Title
        [users_username] => John
    )
[1] => stdClass Object
    (
        [task_id] => 2
        [task_title] => Title
        [users_username] => John
    )
[2] => stdClass Object
    (
        [task_id] => 3
        [task_title] => Title
        [users_username] => Mike
    )
)

I'd like to reorder it to get multi-arrays by user_name, so I can cycle through the task by username.

Array
(
    [John] => Array
        (
            [0] => Array
                (
                    [task_id] => 1
                    [title] => Title
                )

            [1] => Array
                (
                    [task_id] => 2
                    [title] => Title
                )

        )

    [Mike] => Array
        (
            [0] => Array
                (
                    [task_id] => 3
                    [title] => Title
                )

        )

)

Is it possible to recreate my array to an array like that above?

Answer 1

Updated version of the code

<?php
$it0 = (object) array('task_id' => 1,'task_title' => 'Title','users_username' => 'John');
$it1 = (object) array('task_id' => 2,'task_title' => 'Title','users_username' => 'John');
$it2 = (object) array('task_id' => 3,'task_title' => 'Title','users_username' => 'Mike');

$array = array($it0,$it1,$it2);

$return = array();
foreach($array as $id => $value){
  $return[$value->users_username][] = array('task_id' => $value->task_id,'title' => $value->task_title);
}

var_dump($return);

Answer 2

Yes, it is possible. You'll have to loop through your current array and create a new array to do it.

example:

$new_array = array();
foreach ($array as $row)
{
    $new_row = array(
        'task_id' => $row->task_id,
        'title' => $row->task_title,
    );
    $name = $row->users_username;

    if (isset($new_array[$name]))
    {
        $new_array[$name][] = $new_row;
    }
    else
    {
        $new_array[$name] = array($new_row);
    }
}

Now $new_array contains the new array exactly like the one you're asking for.

Then you can sort it with

ksort($new_array);

Answer 3

There may be another way to do this, with some built-in function, but sometimes I'd rather just do it myself, and know how it is working, without having to look up the documentation.

The approach:

Iterate through all of the first array, looking at [users_username] and putting them into a new array.

Code:

$dst_array = array();
foreach ($src_array as $val)
{
     $user = $val->users_username;

     // TODO: This check may be unnecessary. Have to test to find out.
     // If this username doesn't already have an array in the destination...
     if (!array_key_exists($user, $dst_array))
         $dst_array[$user] = array();  // Create a new array for that username

     // Now add a new task_id and title entry in that username's array
     $dst_array[$user][] = array(
         'task_id' => $val->task_id
         'title' => $val->title
     );
}

Answer 4

Just something like this (maybe not 100% PHP code):

foreach ( $obj : $oldArray ) {
  $newTask['task_id'] = $obj->task_id;
  $newTask['title'] = $obj->title;

  $newArray[$oldName][] = $newTask;
}

If you want to order it; you can just call a order function afterwards.