抽奖概率 php

<?php
class Lottery {
    private $probabilities;

    public function __construct($probabilities) {
        $this->probabilities = $probabilities;
    }

    public function draw() {
        $total = array_sum($this->probabilities);
        $rand = mt_rand(1, $total);

        $sum = 0;
        foreach ($this->probabilities as $key => $probability) {
            $sum += $probability;
            if ($rand <= $sum) {
                return $key;
            }
        }
    }
}

// 示例概率数组
$probabilities = [
    '一等奖' => 1,
    '二等奖' => 5,
    '三等奖' => 10,
    '谢谢参与' => 84
];

$lottery = new Lottery($probabilities);

// 抽奖
$result = $lottery->draw();
echo "恭喜你获得了: " . $result . "\n";
?>