php - adding object to sub-array

Question

I need to group array by date but not working. unable to push object into sub array. below are my tried code.

$getData = array
(
    0 => array
    (
        'date' => '2017-08-22',
        'msg' => '1231',
    ),
    1 => array
    (
        'date' => '2017-08-21',
        'msg' => '1172',
    ),
    2 => array
    (
        'date' => '2017-08-20',
        'msg' => '1125'
    ),
    3 => array
    (
        'date' => '2017-08-21',
        'msg' => '251'
    ),
    4 => array
    (
        'date' => '2017-08-20',
        'msg' => '21773',
    ),
    5 => array
    (
        'date' => '2017-08-22',
        'msg' => '3750'
    )
);
$smsArr = [];
foreach ($getData as $xyz => $groupData) {
    $isFound = FALSE;
    $abc['date'] = $groupData['date'];
    $abc['data'] = [(object)["msg" => $groupData['msg']]];
    foreach ($smsArr as $key => $value) {
        if ($value['date'] == $groupData['date']) {
            array_push($value['data'], (object)["msg" => $groupData['msg']]); // nothing happens to final array
            $isFound = TRUE;
        }
    }
    if ($isFound == FALSE) {
        array_push($smsArr, $abc);
    }


}
print_r($smsArr);

trying to group json by date. but when trying to push element to sub array nothing happens.

i should get final result

Array
(
    [0] => Array
    (
        [date] => 2017 - 08 - 21
        [data] => Array
        (
            [0] => stdClass Object
            (
                [msg] => 1172
            )
            [1] => stdClass Object
            (
                [msg] => 251
            )
        )
    )

    [1] => Array
    (
        [date] => 2017 - 08 - 20
        [data] => Array
        (
            [0] => stdClass Object
            (
                [msg] => 1125
            )
            [1] => stdClass Object
            (
                [msg] => 21773
            )
        )
    )
    
    [2] => Array
    (
        [date] => 2017 - 08 - 21
        [data] => Array
        (
            [0] => stdClass Object
            (
                [msg] => 3750
            )
            [1] => stdClass Object
            (
                [msg] => 1231
            )
        )
    )
)

when I trying push array_push($value['data'],(object)["msg"=>$groupData['msg']]);

it does not reflect on final array.

Answer 1

When you want to change the array in foreach you should pass its value by reference. so the line:

foreach ($smsArr as $key => $value)

change it to

foreach ($smsArr as $key => &$value)

now when you change the $value, $smsArr will change. this document will help you to know more about the concept. https://www.php.net/manual/en/language.references.pass.php