php - 如何用php给分数打分

Question

我正在尝试根据获得的最高平均值对一些分数进行评分。这是我的脚本

$scores_AND_ID = 'M2377O=100,M2727B=100,M5821K=100,M7492F=97.75,M7973O=96,M3487I=94,M7969O=93.13,M1452V=92.5,M4653O=92.38,M4158J=92.25,M2881A=89.38,M6112S=28.63,';
    $out_score = chop($scores_AND_ID, ',');
    $rr2 = explode(",", $out_score);


    $array_un = array_unique($rr2);
    foreach ($array_un as $key => $value) {
        if ($value == "") {
            continue;
        }


        $postion = positionNumbers($key);//1st,2nd,3rd function
        $sec = explode("=", $value);
        rsort($sec);
        $stdntID = $sec[0]; //Student number
        $stdntAV = $sec[1]; //Student Average

        mysql_query("UPDATE score_table SET grade='$postion' WHERE avg='$stdntAV' ");

    }

我正在使用 foreach 键来分配成绩位置，但无法正常工作。 这是我的结果

这就是我需要实现的目标。

    1. 100---1st
    2. 100---1st
    3. 100---1st
    4. 98---4th
    5. 89.5--5th
    6. 89---6th
    7. 89---6th
    8. 80---8th

谢谢大家

Answer 1

我认为你想要的代码是这样的:

<?php

$scores_AND_ID = 'M7492F=97.75,M7973O=96,M3487I=94,M2377O=100,M2727B=100,M5821K=100,M7969O=93.13,M1452V=92.5,M4653O=92.38,M4158J=92.25,M2881A=89.38,M6112S=28.63,';

// Gets all of the entries from the source string
$scores_array = array_unique(array_filter(explode(',', $scores_AND_ID)));

// Sets up an associative array of values (student id => score)
$score_map = [];
foreach ($scores_array as $record) {
    [ $student_id, $score ] = explode('=', $record);

    $score_map[$student_id] = $score;
}

// Ensure values are sorted numerically descending
uasort($score_map, function ($a, $b) {
    if ($a > $b) {
        return -1;
    }
    if ($a == $b) {
        return 0;
    }

    return 1;
});

// Gets the maximum value from the scores
$previous_score = max(array_values($score_map));

$rank = 1;
$incrementer = 0;
foreach ($score_map as $student => $score) {
    // If the score hasn't changed from it's previous value
    // we increment a counter instead of the rank
    if ($score == $previous_score) {
        $incrementer++;
    // Once it's changed, we update the rank based on the incrementer
    // and then reset the incrementer
    } else {
        $rank += $incrementer;
        $incrementer = 1;
    }

    $previous_score = $score;

    // Updating database is left as an exercise to the reader
}