概率算法抽奖活动中用得是最多的了，下面就直接上代码：

<?php
/**
 * Author: Dcr163
 * Date: 2022/3/25
 * Time: 10:25
 */

/**
 * 获取中奖奖品下标 区间模式
 * @param array $prizeList
 * @return int|string|null
 */
function beganToDrawBetween(array $prizeList)
{
    //总概率统计
    $sumRatio = array_sum(array_column($prizeList, 'ratio'));

    // 初始化随机数，奖品区间
    $randNum = mt_rand(1, $sumRatio);
    $leftInterval = 0;
    $rightInterval = 0;
    $lastRightInterval = 0;

    foreach ($prizeList as $k => $prize) {
        // 左区间
        $leftInterval = $lastRightInterval;
        // 右区间
        $rightInterval = $leftInterval + $prize['ratio'];
        // 上一个右区间
        $lastRightInterval = $rightInterval;
        // 判断随机数是否落在对应的区间
        if ($leftInterval < $randNum && $randNum <= $rightInterval) {
            return $k;
        }
    }
}

//模拟奖品列表
$prizeList = [
    [
        'id' => 1,
        'prize_name' => '华为手机P50',
        'ratio' => 1,
    ],
    [
        'id' => 2,
        'prize_name' => '宝马X5',
        'ratio' => 0,
    ],
    [
        'id' => 3,
        'prize_name' => '魅族蓝牙耳机',
        'ratio' => 20,
    ],
    [
        'id' => 4,
        'prize_name' => '魔域手机清洁包',
        'ratio' => 60,
    ],
    [
        'id' => 5,
        'prize_name' => '医用冷敷面膜',
        'ratio' => 40,
    ],
    [
        'id' => 6,
        'prize_name' => '激光祛痘',
        'ratio' => 30,
    ],
    [
        'id' => 7,
        'prize_name' => '神秘盲盒',
        'ratio' => 80,
    ],
    [
        'id' => 8,
        'prize_name' => '高级写字笔',
        'ratio' => 90,
    ],
    [
        'id' => 9,
        'prize_name' => '熊猫公仔min',
        'ratio' => 90,
    ],
    [
        'id' => 10,
        'prize_name' => '熊猫公仔Plush',
        'ratio' => 70,
    ],
];


//已中奖奖品数据
$luckyData = [];
//模拟10000次抽奖操作
for ($i = 1; $i <= 10000; $i++) {
    $prizeIndex = beganToDrawBetween($prizeList);
    if (is_null($prizeIndex)) continue;
    $luckyData[] = $prizeList[$prizeIndex];
}

$html = '<table>';
$html .= '<th>';
$html .= '<td>奖品ID</td>';
$html .= '<td>奖品名称</td>';
$html .= '<td>中奖率</td>';
$html .= '</th>';
foreach ($luckyData as $prize) {
    $html .= '<tr>';
    $html .= '<td>' . $prize['id'] . '</td>';
    $html .= '<td>' . $prize['prize_name'] . '</td>';
    $html .= '<td>' . $prize['ratio'] . '</td>';
    $html .= '<tr>';
}
$html .= '</table>';

echo $html;

经过10000次测试，比例越高的中奖率越高，此时抽奖算法已经达到需求