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Php versions – how to delete specific index with comparing

i want to delete some index with comparing but it is not easy

first one our php version is 5
for example my result is like this
it is echo by json_encode and it was array
and the data is dynamic

[
        {
            "idx": "1",
            "mom_member_idx": "1",
            "teacher_member_idx": "2",
            "care_start_datetime": "2019-09-09 08:30:00",
         },

        {
            "idx": "2",
            "mom_member_idx": "1",
            "teacher_member_idx": "2",
            "care_start_datetime": "2019-09-10 08:30:00",
         },
         {
            "idx": "3",
            "mom_member_idx": "2",
            "teacher_member_idx": "2",
            "care_start_datetime": "2019-09-09 08:30:00",
         }

]

and i want to result like this comparing and unset with the latest one

[
        {
            "idx": "1",
            "mom_member_idx": "1",
            "teacher_member_idx": "2",
            "care_start_datetime": "2019-09-09 08:30:00",
         },
         {
            "idx": "3",
            "mom_member_idx": "2",
            "teacher_member_idx": "2",
            "care_start_datetime": "2019-09-09 08:30:00",
         }

]

i tried like this but it is not work

while ($r = mysqli_fetch_assoc($chat_list)) {
    $dbdata[] = $r;
}
for($r=0;$r<sizeof($dbdata);$r++){
    if ($dbdata[$r]['mom_member_idx']+$dbdata[$r]['teacher_member_idx']==$dbdata[$r+1]['mom_member_idx']+$dbdata[$r+1]['teacher_member_idx'])
    {
        if($dbdata[$r]['care_start_datetime']<$dbdata[$r+1]['care_start_datetime']){
            unset($dbdata[$r]);
        }else {
            unset($dbdata[$r+1]);
        }
    }
}
Tags:

4

Answers


  1. 0

    First, convert your JSON array into a PHP array. then you can remove the array elements using the array index

    $someArray = json_decode($someJSON, true);

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  2. 0

    For delete specific index first you need to convert JSON array into PHP array using json_decode() function, once you convert it into PHP array you can remove specific index using key,

    foreach ($data as $key => $element) {
    $value = $element['...'];
    if (...) {
        unset($data[$key]);
        // or
        $data[$key]['...'] = '...';
    }
}

    Hope this helps you.

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  3. 0

    Your variant with summing to columns is not totally correct, because sum of some integers give you wrong result and you can accidentally remove the wrong one. Like 2 + 3 == 1 + 4 not correct.

    Maybe that code helps you:

    $groupedData = array();
while ($r = mysqli_fetch_assoc($chat_list)) {
    // We create unique key for group same rows
    // (with the same 'mom_member_idx' and 'teacher_member_idx')
    $uniqueKey = implode('_', [$r['mom_member_idx'], $r['teacher_member_idx']]);

    if (!array_key_exists($uniqueKey, $groupedData)) {
        $groupedData[$uniqueKey] = array();
    }

    // Add row to grouped array by our unique key
    $groupedData[$uniqueKey][] = $row;
}

$result = array();
foreach ($groupedData as $rows) {
    // If in grouped array with that unique key only one row - just add it
    if (count($rows) <= 1) {
        $result[] = $rows[0];

        continue;
    }

    // Go for all same rows and check date
    $neededRow = null;
    foreach ($rows as $row) {
        // Here I don't understand what kind of date do you want - minimum or maximum
        // You just can reverse the sign
        if (
            is_null($neededRow) ||
            strtotime($row['care_start_datetime']) > strtotime($neededRow['care_start_datetime'])
        ) {
            $neededRow = $row
        }
    }

    if ($neededRow) {
        $result[] = $neededRow;
    }
}
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  4. 0

    You can sort the data by descending order by care_start_datetime using usort() and unset the first index form that sorted data.

    Code example:

    $data = json_decode('[
    {"idx": "1","mom_member_idx": "1","teacher_member_idx": "2","care_start_datetime": "2019-09-09 08:30:00"},
    {"idx": "2","mom_member_idx": "1","teacher_member_idx": "2","care_start_datetime": "2019-09-10 08:30:00"},
    {"idx": "3","mom_member_idx": "2","teacher_member_idx": "2","care_start_datetime": "2019-09-09 08:30:00"}
]', true);

usort($data, function($a, $b) { 
    return strtotime($a['care_start_datetime']) > strtotime($b['care_start_datetime']) ? -1 : 1; 
});
unset($data[0]);

print_r($data);

    Working demo.

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