How to group subarrays by a column value?

Question

I have the following array

Array
(
    [0] => Array
        (
            [id] => 96
            [shipping_no] => 212755-1
            [part_no] =&         


        

Answer 1

Recursive function grouping 2-dimensional array by keys from first to last

Input:

$arr = array(
    '0' => array(
        'key0' => 'value0',
        'key1' => 'value1',
        'key2' => 'value02',
    ),
    '2' => array(
        'key0' => 'value0',
        'key1' => 'value1',
        'key2' => 'value12',
    ),
    '3' => array(
        'key0' => 'value0',
        'key1' => 'value3',
        'key2' => 'value22',
    ),
);
$keys = array('key0', 'key1', 'key2');

Output:

$arr = array(
    'value0' => array(
        'value1 => array(
            'value02' => null,
            'value12' => null,
        ),
        'value3' => 'value22',
    ),
);

Code:

function array_group_by_keys(&$arr, $keys) {

    if (count($arr) < 2){
        $arr = array_shift($arr[0]);
        return;
    }

    foreach ($arr as $k => $item) {
        $fvalue = array_shift($item);
        $arr[$fvalue][] = $item;
        unset($arr[$k]);
    }

    array_shift($keys);
    foreach ($arr as &$sub_arr) {
        array_group_by_keys($sub_arr, $keys);
    }
}

Answer 2

Consume and cache the column value that you want to group by, then push the remaining data as a new subarray of the group you have created in the the result.

function array_group(array $data, $by_column)
{
    $result = [];
    foreach ($data as $item) {
        $column = $item[$by_column];
        unset($item[$by_column]);
        $result[$column][] = $item;
    }
    return $result;
}

Answer 3

function array_group_by($arr, array $keys) {

if (!is_array($arr)) {
    trigger_error('array_group_by(): The first argument should be an array', E_USER_ERROR);
}
if (count($keys)==0) {
    trigger_error('array_group_by(): The Second argument Array can not be empty', E_USER_ERROR);
}

// Load the new array, splitting by the target key
$grouped = [];
foreach ($arr as $value) {
    $grouped[$value[$keys[0]]][] = $value;
}

// Recursively build a nested grouping if more parameters are supplied
// Each grouped array value is grouped according to the next sequential key
if (count($keys) > 1) {
        foreach ($grouped as $key => $value) {
       $parms = array_merge([$value], [array_slice($keys, 1,count($keys))]);
       $grouped[$key] = call_user_func_array('array_group_by', $parms);

    }
}
return $grouped;

}

Answer 4

There is no native one, just use a loop.

$result = array();
foreach ($data as $element) {
    $result[$element['id']][] = $element;
}

Answer 5

$arr = array();

foreach($old_arr as $key => $item)
{
   $arr[$item['id']][$key] = $item;
}

ksort($arr, SORT_NUMERIC);

Answer 6

Check indexed function from Nspl:

use function \nspl\a\indexed;
$grouped = indexed($data, 'id');