Remove Array list object if its date(property) is with in 15 days with respect to any other object date

Question

I'll clarify my question.

I have array list of objects, where one of its property is date. I want a list of objects where their is a minimum gap of 15 days between each object in the array.

    {
        "id": 1,
        "date" : "21-04-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }
    {
        "id": 2,
        "dateReported" : "29-03-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 3,
        "dateReported" : "29-03-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 4,
        "dateReported" : "23-03-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 5,
        "dateReported" : "02-02-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 6,
        "dateReported" : "01-02-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }`

In the above list, Object id: 1, 2, 5 has to be the result because for example object id: 3 is within 15 days of object id: 2 and similarly id: 4 and object id:6 is within 15days of object id:5.

I have written following code, where I am able to remove object id: 3 and 6 within a loop but I am not able to remove object id:4 which is also within 15 days of object id:2

Following is the php code which I tried:

$finalFilteredList = [];
// Filter out array objects, if any array objects have dates with in 15 days.
for ($index = 0, $j = 0; $index < count($intermediateList); $index++) {
    $counter = $index + 1;
    if (isset($intermediateList[$counter])) {
        // Find the difference between counter date and index date.
        $diffTimePeriod = date_diff(date_create($intermediateList[$counter]['date']), date_create($intermediateList[$index]['date']));
        $diffInDays = $diffTimePeriod->format('%d') + (30 * $diffTimePeriod->format('%m')) + (360 * $diffTimePeriod->format('%y'));
        if ($diffInDays < 15) {
            // Considering as duplicate entry and hence ignoring.
        } else {
            $finalFilteredList[$j] = $intermediateList[$index];
            $j++;
        }
    }
}

I believe the array has to be sorted for my above code to work and I assuming that it is sorted for now(to reduce the complexity).

Answer 1

Try this:

$jsonStr = '[{
        "id": "1",
        "dateReported" : "21-04-2017",
        "report" : "Temp",
        "Test" : "7500000"
    },
    {
        "id": "2",
        "dateReported" : "29-03-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 3,
        "dateReported" : "29-03-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 4,
        "dateReported" : "23-03-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 5,
        "dateReported" : "02-02-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }, 
    {
        "id": 6,
        "dateReported" : "01-02-2017",
        "report" : "Temp",
        "Test" : "7500000"
    }]';
   $intermediateList = json_decode($jsonStr);
   $finalFilteredList = array();
   for ($index = 0, $j = 0; $index < count($intermediateList); $index++) {
       $counter = $index + 1;
       if (isset($intermediateList[$counter])) { 
            $datediff =  strtotime($intermediateList[$index]->dateReported) - strtotime($intermediateList[$counter]->dateReported);
            $datediffInDays = floor($datediff / (60 * 60 * 24));
            if($datediffInDays >= 15){ 
                if(empty($finalFilteredList)){
                    $finalFilteredList[] = $intermediateList[$index];
                    $finalFilteredList[] = $intermediateList[$counter];
                }else{
                    $finalFilteredList[] = $intermediateList[$counter];
                }
            }
       }
   }
echo "<pre>"; 
print_r($finalFilteredList); 

Check Code Snippet

Answer 2

If your list is already sorted by date, something like below could be more readable:

$sortedList = [...your sorted list...];
$filteredList = [];
$firstItem = array_shift($sortedList);
$filteredList[] = $firstItem;
$currentDate = DateTime::createFromFormat('d-m-Y', $firstItem['dateReported']);

foreach($sortedList as $item){

    $nextDate = DateTime::createFromFormat('d-m-Y', $item['dateReported']);
    $interval = $currentDate->diff($nextDate);

    if($interval->days < 15){ continue;}

    $currentDate = $nextDate;
    $filteredList[] = $item;

}