Question

我想通过比较删除一些索引，但这并不容易

第一个我们的php版本是5 例如我的结果是这样的它由json_encode回显，它是数组数据是动态的

[
        {
            "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",
         }

]

我想要这样的结果与最新的结果进行比较并取消设置

[
        {
            "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",
         }

]

我这样尝试过，但是不起作用

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]);
        }
    }
}

Answer 1

您可以使用usort()和care_start_datetime排序数据的第一个索引形式按unset降序对数据进行排序。

代码示例：

$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);

工作demo。

Answer 2

首先，将JSON数组转换为PHP数组。那么您可以使用数组索引

删除数组元素

$ someArray = json_decode（$ someJSON，true）;

Answer 3

首先要删除特定索引，您需要使用json_decode（）函数将JSON数组转换为PHP数组，将其转换为PHP数组后，您可以使用键删除特定索引，

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

希望这对您有所帮助。

Answer 4

您对列求和的变体并不完全正确，因为某些整数的和会给您错误的结果，并且您可能会意外删除错误的结果。像2 + 3 == 1 + 4一样不正确。

也许该代码可以帮助您：

$groupedData = array();
while ($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;
    }
}

如何通过比较删除特定索引

4 个答案: