Sort array using PHP - group by key value

Question

I grab data by running a cURL operation and then use:

<?php
    $data = json_decode($result, true);
    print_r($data)
?>

to output:

Array
(
    [0] => Array
        (
            [id] => 258378365
            [firstName] => Test
            [lastName] => McTest
            [phone] => 1235550101
            [email] => test.mctest@example.com
            [date] => January 10, 2019
        )

    [1] => Array
        (
            [id] => 253994842
            [firstName] => Jane
            [lastName] => McTest
            [phone] => 1235550101
            [email] => jane.mctest@example.com
            [date] => December 13, 2018
        )

    [2] => Array
        (
            [id] => 253994843
            [firstName] => Jane
            [lastName] => McTest
            [phone] => 1235550101
            [email] => jane.mctest@example.com
            [date] => January 10, 2019
        )

)

Is it possible to group my results by date ?

I can display my results like this:

<?php
foreach($data as $entry){
    echo $entry['id'];
}
?>

However, I'd like to group my results by $entry['date']

How do I achieve this?

Answer 1

uasort($data, function($a, $b) {
    return strtotime($a['date']) > strtotime($b['date']);
});

Answer 2

The following will sort the array by date in ascending order.

usort($data, function ($x,$y) {
    return strtotime($x['date']) - strtotime($y['date']);
});

_Edit: I may have misunderstood the question so if the intent is to retrieve only the dates in a separate array then perform the following:

$dates = array_column($data, 'date');

If you needed the dates sorted after this then perform the usort example above by passing the $dates array as follows:

usort($dates, function ($x,$y) {
    return strtotime($x) - strtotime($y);
});