another report for data from https://github.com/ronnywang/portal.sw.nat.gov.tw/

report1.php

<?php

$rFh = fopen(__DIR__ . '/report1.csv', 'w');
fputcsv($rFh, array('代碼', '<=97', '>97', '+/-', '差異數', '變動比例'));

$stack = array();
foreach (glob(dirname(__DIR__) . '/goods/good_in/*-4code.csv') AS $csvFile) {
    $p = pathinfo($csvFile);
    /*
     * Array
      (
      [0] => 100
      [1] => 1
      [2] => 4code
      )
     */
    $f = explode('-', $p['filename']);
    $fh = fopen($csvFile, 'r');
    fgetcsv($fh, 512);
    while ($line = fgetcsv($fh, 2048)) {
        /*
         * Array
          (
          [0] => 貨品分類
          [1] => 國家
          [2] => 重量
          [3] => 重量單位
          [4] => 價值
          )
         */
        if ($line[1] === '合計' && $f[0] < 103) {
            if (!isset($stack[$line[0]])) {
                $stack[$line[0]] = array();
                for ($i = 92; $i < 103; $i++) {
                    $stack[$line[0]][$i] = 0;
                }
            }
            $stack[$line[0]][$f[0]] += $line[2];
        }
    }
    fclose($fh);
}
$result = array();
foreach ($stack AS $code => $years) {
    $result[$code] = array(
        '<=97' => array(
            'total' => 0,
            'count' => 0,
            'avg' => 0,
        ),
        '>97' => array(
            'total' => 0,
            'count' => 0,
            'avg' => 0,
        ),
    );
    foreach ($years AS $year => $weight) {
        if ($weight > 0) {
            if ($year > 97) {
                $result[$code]['>97']['count'] ++;
                $result[$code]['>97']['total'] += $weight;
            } else {
                $result[$code]['<=97']['count'] ++;
                $result[$code]['<=97']['total'] += $weight;
            }
        }
    }
    foreach ($result[$code] AS $k => $v) {
        if ($result[$code][$k]['count'] > 0) {
            $result[$code][$k]['avg'] = round($result[$code][$k]['total'] / $result[$code][$k]['count']);
        }
    }
    $diff = abs($result[$code]['<=97']['avg'] - $result[$code]['>97']['avg']);
    fputcsv($rFh, array(
        $code . '-',
        $result[$code]['<=97']['avg'],
        $result[$code]['>97']['avg'],
        $result[$code]['>97']['avg'] >= $result[$code]['<=97']['avg'] ? '+' : '-',
        $diff,
        $result[$code]['<=97']['avg'] > 0 ? round($diff / $result[$code]['<=97']['avg'], 2) : 0,
    ));
}
fclose($rFh);