从php的对象数组中获取所有最大值

Question

我在mysql中从query中获得了这个对象数组，我需要

  [
                {
                    "id": "11",
                    "from_userid": "1996",
                    "contest_id": "29",
                    "to_userid": "8",
                    "vote_date": "2020-10-06 01:40:04",
                    "count_votes": "1"
                },
                {
                    "id": "1",
                    "from_userid": "82",
                    "contest_id": "29",
                    "to_userid": "94",
                    "vote_date": "2020-09-03 07:06:36",
                    "count_votes": "1"
                },
               {
                    "id": "2",
                    "from_userid": "82",
                    "contest_id": "29",
                    "to_userid": "98",
                    "vote_date": "2020-09-03 07:06:36",
                    "count_votes": "0"
                }
            ]

我需要的对象有最高的'count_votes‘为例如- id-11和1有类似的计数投票。所以函数应该返回这两个对象。

我使用的函数只返回一个对象。我需要这两个对象，除了最高的(Count_votes)对象。预期输出-

 [
                {
                    "id": "11",
                    "from_userid": "1996",
                    "contest_id": "29",
                    "to_userid": "8",
                    "vote_date": "2020-10-06 01:40:04",
                    "count_votes": "1"
                },
                {
                    "id": "1",
                    "from_userid": "82",
                    "contest_id": "29",
                    "to_userid": "94",
                    "vote_date": "2020-09-03 07:06:36",
                    "count_votes": "1"
                }
]

使用的函数-

function max_attribute_in_array($array, $prop) {
    return max(array_map(function($o) use($prop) {
                            return $o;
                         },
                         $array));
}

我也试过了-

function get_highest($arr) {
    $max = $arr[0]; // set the highest object to the first one in the array
    foreach($arr as $obj) { // loop through every object in the array
        $num = $obj['count_votes']; // get the number from the current object
        if($num > $max['count_votes']) { // If the number of the current object is greater than the maxs number:
            $max = $obj; // set the max to the current object
        }
    }
    return $max; // Loop is complete, so we have found our max and can return the max object
}

Answer 1

您可以使用array_column将所有count_votes值提取到一个数组中，然后您可以获取以下内容的max：

$max = max(array_column($arr, 'count_votes'));

然后，可以根据等于$max的count_votes值对数组执行array_filter操作

$out = array_filter($arr, function ($o) use ($max) {
    return $o['count_votes'] == $max;
});

输出：

Array
(
    [0] => Array
        (
            [id] => 11
            [from_userid] => 1996
            [contest_id] => 29
            [to_userid] => 8
            [vote_date] => 2020-10-06 01:40:04
            [count_votes] => 1
        )
    [1] => Array
        (
            [id] => 1
            [from_userid] => 82
            [contest_id] => 29
            [to_userid] => 94
            [vote_date] => 2020-09-03 07:06:36
            [count_votes] => 1
        )
)

Demo on 3v4l.org

Answer 2

注max与单级数组一起工作，因此所有对象都会在内部转换为整数。

正如@Nick所指出的，你的get_highest可以通过PHP函数来实现：

function get_highest($array, $prop) {
    return max(array_column($array, $prop));
}

因此，您所要做的就是根据此get_highest过滤数组

$max = get_highest($myArray, 'count_votes');

$maxes = array_filter($myArray, fn($obj) => $obj['count_votes'] === $max);

Answer 3

function get_heighest($arr){
    $newArray = array();
    $voteCount = 0;

    foreach($arr as $obj){
        if($obj['count_votes'] >= $voteCount){
            array_push($newArray, $obj)
            $voteCount = $obj['count_votes'];
        }else{
            $i = 0;
            foreach($newArray as $object){
                if($object['count_votes'] < $voteCount){
                    unset($newArray[$i]);
                }
                $i++;
            }
        }
    }
    return $newArray;
}