Question

I have an array that contains multiple objects with many properties.

I want to sort it in PHP base on two object properties

Here’s a sample array of objects to give you an idea of what data i’m dealing with:

Array (
    [0] => stdClass Object (
        [username] => user98
        [sender_id] => 98
        [date_sent] => 2012-07-25 00:52:11
        [not_read] => 0
    )
    [1] => stdClass Object (
        [username] => user87
        [sender_id] => 87
        [date_sent] => 2012-07-25 00:59:15
        [not_read] => 1
    )
    [2] => stdClass Object (
        [username] => user93
        [sender_id] => 93
        [date_sent] => 2012-07-25 00:52:13
        [not_read] => 2
    )
    [3] => stdClass Object (
        [username] => user5
        [sender_id] => 5
        [date_sent] => 2012-07-25 00:52:16
        [not_read] => 0
    )
)

I need to sort it resulting to this array:

Array (
    [1] => stdClass Object (
        [username] => user87
        [sender_id] => 87
        [date_sent] => 2012-07-25 00:59:15
        [not_read] => 1
    )
    [2] => stdClass Object (
        [username] => user93
        [sender_id] => 93
        [date_sent] => 2012-07-25 00:52:13
        [not_read] => 2
    )
    [3] => stdClass Object (
        [username] => user5
        [sender_id] => 5
        [date_sent] => 2012-07-25 00:52:16
        [not_read] => 0
    )

    [0] => stdClass Object (
        [username] => user98
        [sender_id] => 98
        [date_sent] => 2012-07-25 00:52:11
        [not_read] => 0
    )


)

The sorting is based on the date property and the not_read property of the object, the not_read > 0 is prioritized first in the sorting, then it will look at the date_sent property and sort it on the latest date_sent. Note that it is not based on who has the higher not_read property.

Then those with 0 not_read property will be sorted by latest date_sent.

Can anyone help me with this program?

thanks a lot of looking!

Answer 1

function sortByDate($a, $b)
{
    if($a->not_read > 0 && $b->not_read == 0)
        return -1;
    if($b->not_read > 0 && $a->not_read == 0)
        return 1;
    if ($a->not_read == 0 && $b->not_read == 0 || $a->not_read > 0 && $b->not_read > 0){
        if(strtotime($a->date_sent) > strtotime($b->date_sent))
            return -1;
        if(strtotime($a->date_sent) < strtotime($b->date_sent))
            return 1;
    }

    return 0;
}

usort($array_to_sort, 'sortByDate');

Note: I would of made an edit to Patrick’s but I wasn’t sure if mine even worked. He was on the right track.