PHP学习笔记：数据分析与挖掘

学号,姓名,年龄,性别,成绩
1001,张三,18,男,80
1002,李四,19,女,85
1003,王五,20,男,92
1004,赵六,19,女,78
1005,刘七,18,男,88
...

$students = file('students.csv');

$sum = 0;
$cnt = 0;

foreach ($students as $student) {
    $data = explode(',', $student);
    if (isset($data[4])) {
        $sum += intval($data[4]);
        $cnt++;
    }
}

$average = $sum / $cnt;

echo '平均成绩：' . $average;

$maleCount = 0;
$femaleCount = 0;

foreach ($students as $student) {
    $data = explode(',', $student);
    if (isset($data[3])) {
        if ($data[3] == '男') {
            $maleCount++;
        } elseif ($data[3] == '女') {
            $femaleCount++;
        }
    }
}

echo '男生人数：' . $maleCount;
echo '女生人数：' . $femaleCount;

$grades = []; // 统计各个成绩段人数

foreach ($students as $student) {
    $data = explode(',', $student);
    if (isset($data[4])) {
        $grade = intval($data[4]);
        if (!isset($grades[$grade])) {
            $grades[$grade] = 1;
        } else {
            $grades[$grade]++;
        }
    }
}

// 使用柱状图展示成绩分布
foreach ($grades as $grade => $count) {
    echo $grade . '分: ' . str_repeat('*', $count) . ' (' . $count . '人)' . PHP_EOL;
}

$topStudents = [];

foreach ($students as $student) {
    $data = explode(',', $student);
    $score = isset($data[4]) ? intval($data[4]) : 0;
    $topStudents[$data[1]] = $score;
}

arsort($topStudents);

$i = 1;
foreach ($topStudents as $name => $score) {
    echo '第' . $i . '名: ' . $name . ' (' . $score . '分)' . PHP_EOL;
    $i++;
    if ($i > 10) {
        break;
    }
}