PHP check if value in array is smaller than previous value in array per ID

Question

I have an array where I store an ID and for every ID there's an array that holds a start and end value. My goal is to check if the start value is smaller than the end value of the item that comes before it in the array.

This works but my loop doesn't care about the ID's, I need a way to do this per ID

Here's what my array looks like:

Array
(
    [892] => Array
        (
            [41] => Array
                (
                    [0] => Array
                        (
                            [start] => 0930
                            [end] => 1200
                        )

                )

        )

    [897] => Array
        (
            [41] => Array
                (
                    [0] => Array
                        (
                            [start] => 1000
                            [end] => 1230
                        )

                )

        )

    [898] => Array
        (
            [41] => Array
                (
                    [0] => Array
                        (
                            [start] => 1100
                            [end] => 1300
                        )

                )

        )

    [901] => Array
        (
            [52] => Array
                (
                    [0] => Array
                        (
                            [start] => 0930
                            [end] => 1030
                        )

                )

        )

    [903] => Array
        (
            [52] => Array
                (
                    [0] => Array
                        (
                            [start] => 0930
                            [end] => 1030
                        )

                )

        )

    [904] => Array
        (
            [41] => Array
                (
                    [0] => Array
                        (
                            [start] => 1000
                            [end] => 1230
                        )

                )

        )

)

And this is what my loop looks like:

$foundOverlap = false;
$prevEnd = null;
foreach($slots as $s){

     $startHour = $s[0]['start'];
     $endHour = $s[0]['end'];
     echo $startHour . '<br>';
     echo $endHour . '<br>';

     if($prevEnd !== null && $startHour < $prevEnd){
         $foundOverlap = true;
         $counter++;
     } 

     if($foundOverlap){
        echo 'overlap <br>';
     }else{
        echo 'no overlap <br>';
     }

     $prevEnd = $endHour;

}

As a result I get No overlap(good), overlap(good), overlap(good), overlap(BAD!) this should be no overlap. But it says overlap because It checks with the previous array item doesn't care what the attractieID is...

Anyone please knows how I can fix this?

I would be soooo thankful!!

Thanks in advance!

You have already asked the same question today. Here is the link (http://stackoverflow.com/questions/36714467/php-check-values-of-array-per-id) — Nehal, Apr 19 '16 at 12:14
@Ms.Nehal I deleted that question since there were some errors with my code — Frank Lucas, Apr 19 '16 at 12:15
save `attractieID` in a variable e.g. `$preID` and update it like `$prevEnd` Then in `if($prevEnd !== null && $startHour < $prevEnd && $currentID == $preID)` — Abbasi, Apr 19 '16 at 12:21
atr to reset `$foundOverlap = true;` every time. use `$foundOverlap = false;` to your foreach loop everytime. — Murad Hasan, Apr 19 '16 at 12:29
@FrayneKonok I am sorry but I do not understand what you're trying to say. — Frank Lucas, Apr 19 '16 at 12:30
check out [my answer](http://stackoverflow.com/questions/36717999/php-check-if-value-in-array-is-smaller-than-previous-value-in-array-per-id/36718521#36718521) to see what i am saying?? — Murad Hasan, Apr 19 '16 at 12:33

Syed mohamed aladeen · Answer 1 · 2016-04-19T12:44:05.557

0

From Muhammad Kashif Abbasi's comment I would like to give you a solution

Try this code

$foundOverlap = false;
$prevEnd = null;
$preID = null;
foreach($slots as $s){

     $startHour = $s[0]['start'];
     $endHour = $s[0]['end'];
     $currentID = $s['attractieID']; //got the current attractieID
     echo $startHour . '<br>';
     echo $endHour . '<br>';

     if($prevEnd !== null && $startHour < $prevEnd && $currentID == $preID){ // checked current id and previous id
         $foundOverlap = true;
         $counter++;
     } 

     if($foundOverlap){
        echo 'overlap <br>';
     }else{
        echo 'no overlap <br>';
     }
     $foundOverlap = false; //reseted $foundOverlap
     $prevEnd = $endHour;
     $preID = $currentID; //set the current id as previous id

}

edited Apr 19 '16 at 12:44

answered Apr 19 '16 at 12:30

Syed mohamed aladeen

6,507
4
32
59

This seem to work, but I have an issue. What if the array is not sorted correctly. Like if you have an item with id 41 then an item with id 52 then again 41. It doesn't seem to work when this occurs. – Frank Lucas Apr 19 '16 at 12:35
you need to pass the array correctly in the order what you want. – Syed mohamed aladeen Apr 19 '16 at 12:44
Do you have any idea how I can sort the array per id? – Frank Lucas Apr 19 '16 at 12:47
1

http://stackoverflow.com/questions/2699086/sort-multi-dimensional-array-by-value check this link to sort – Syed mohamed aladeen Apr 19 '16 at 12:50
`usort($slots, function($a, $b) { return $a['attractieID'] - $b['attractieID']; });` – Abbasi Apr 19 '16 at 12:52
@MuhammadKashifAbbasi My array looks a bit different I updated OP check it out if you want :) – Frank Lucas Apr 19 '16 at 12:54
@SyedMohamedAladeen My array looks a bit different I updated OP check it out if you want. :) – Frank Lucas Apr 19 '16 at 12:54
@FrankLucas that was fast..:P I think its better to have `attractieID` key, as it will help you for sorting. – Abbasi Apr 19 '16 at 12:55
@MuhammadKashifAbbasi I mean this is what my array looks like before I tried your code. Your code to sort it doesn't work unfortunately :( – Frank Lucas Apr 19 '16 at 12:56

score 0 · Answer 2 · answered Apr 19 '16 at 12:31

check this out

$result = [];
foreach($array as $element) {
    if(!isset($result[$element['attractiveID']])) {
        $result[$element['attractiveID']]['overlap'] = false;
        $result[$element['attractiveID']]['prevHour'] = $element[0]['end'];
        continue;
    }

    if($element[0]['start'] < $result[$element['attractiveID']]['prevHour']) {
        $result[$element['attractiveID']]['overlap'] = true;
    }

    $result[$element['attractiveID']]['prevHour'] = $element[0]['end'];
}

and array passed:

$array = [
    [
        'attractiveID' => 41,
        [
            'start' => 930,
            'end' => 1200
        ]
    ],
    [
        'attractiveID' => 41,
        [
            'start' => 1000,
            'end' => 1230
        ]
    ],
    [
        'attractiveID' => 41,
        [
            'start' => 1100,
            'end' => 1300
        ]
    ],
    [
        'attractiveID' => 52,
        [
            'start' => 1000,
            'end' => 1230
        ]
    ],
];

PHP check if value in array is smaller than previous value in array per ID

2 Answers2