Xtykutl

Could an array be sorted by multiple dates, see example source below

Array

(

[0] => Array

    (

        [Name] => Test

        [StartDate] => 2018-09-01 00:00:00

        [EndDate] => 2018-09-07 00:00:00

        [Days] => 7

    )



[1] => Array

    (

        [Name] => Another Test

        [StartDate] => 2018-11-05 00:00:00

        [EndDate] => 2018-11-12 00:00:00

        [Days] => 8

    )

[2] => Array

    (

        [Name] => Something Else

        [StartDate] => 2018-09-08 00:00:00

        [EndDate] => 2018-10-01 00:00:00

        [Days] => 24

    )

[3] => Array

    (

        [Name] => Other

        [StartDate] => 2018-11-13 00:00:00

        [EndDate] => 2018-11-13 00:00:00

        [Days] => 1

    )

)

I've been trying to figure out how to re-arrange the array so that the array will be sorted by the start date, which I've managed to figure out perfectly.

What I'm struggling the most with is looping through the array again and re-arranging the array once more, so that the next event start date is > previous event end date, So what I would like to achieve is the order of 'Test', 'Something Else', 'Another Test', 'Other'

I've recently gotten to grips with arrays and learning quite quickly however I'm still a beginner, any help would be greatly appreciated.

You should define a custom comparator. Something like:

function cmp($a, $b)

{

    if ($a.endDate== $b.startDate) {

        return 0;

    }

    return ($a.endDate < $b.startDate) ? -1 : 1;

}



usort($a, "cmp");

EDIT

To further explain what is happening. When you call a sorting function, whatever the underlying algorithm is it compares the elements to decide which one comes first. This order is trivially defined on primitive types (e.g. 1 is obviously less then 2), but on objects you may need to define how you want them to be ordered.

In your case, you want that when you compare two objects, you want to apply some criteria based on the ending and starting date. That is what you do with a custom comparator.

A comparator receives two elements to compare. It compares them, and if they are equal it returns 0. If the first one must be placed before the second one, it returns -1. If the first one must be placed after the second one, it returns +1. No other return values accepted.