抽奖函数升级版

可自定义概率，按需求排除奖项 无 ?php/** * 抽奖函数升级版，可排除若干奖项 */class Lottery { static public $rate; static public $ignore; /** * * @param type $rate 概率设置 * @param type $ignore 忽略的奖项 * @return 调用实例化后的对象方法 * @e

可自定义概率，按需求排除奖项

<?php

/**
 * 抽奖函数升级版，可排除若干奖项
 */
class Lottery {

    static public $rate;
    static public $ignore;

    /**
     * 
     * @param type $rate 概率设置
     * @param type $ignore 忽略的奖项
     * @return 调用实例化后的对象方法
     * @example Lottery::runOnce(array(20, 10, 10, 10), array(0));
     */
    static public function runOnce($rate = array(10, 10, 10, 10), $ignore = array()) {
        self::$rate = $rate;
        self::$ignore = $ignore;
        $obj = new self;
        return $obj->lotteryProcess();
    }

    /**
     * 处理抽奖
     * @return type
     */
    public function lotteryProcess() {
        $rateSum = array_sum(self::$rate); //概率之和
        //考虑用户输入的概率之和不等于100
        if ($rateSum < 100) {
            array_push(self::$rate, 100 - $rateSum);
        } elseif ($rateSum > 100) {
            die('The rate sum over 100%!');
        }
        //处理忽略奖项
        $rateCount = count(self::$rate);
        foreach (self::$rate as $key => $value) {
            if (in_array($key, self::$ignore)) {
                self::$rate[$rateCount - 1]+=self::$rate[$key];
                self::$rate[$key] = 0;
            }
            $seedRaw[$key] = self::$rate[$key] * 100; //概率放大100被备用
        }
        $seed = $this->arraySum($seedRaw); //处理数组
        $randVal = mt_rand(0, 10000);
        return $this->judge($seed, $randVal);
    }

    /**
     * 从0-10000重新组织数组,每个值为之前各项的累加
     * @param array $seedRaw
     * @return array
     */
    private function arraySum(array$seedRaw) {
        foreach ($seedRaw as $key => $value) {
            $tmpSum = 0;
            for ($i = 0; $i < $key; $i++) {
                $tmpSum+=$seedRaw[$i];
            }
            $seed[$key] = $tmpSum;
        }
        array_push($seed, 10000);
        return $seed;
    }

    /**
     * 根据随机值判断此次中了第几个奖项
     * @param type $seed
     * @param type $rand
     * @return int
     */
    private function judge($seed, $rand) {
        array_push($seed, NULL); //凑数
        for ($i = 0; $i < count($seed) - 1; $i++) {

            if ($rand >= $seed[$i] && $rand < $seed[$i + 1]) {
                return $i;
            }
        }
    }

}

ini_set('display_errors', 'on');

$l0 = 0;
$l1 = 0;
$l2 = 0;
$l3 = 0;
$l4 = 0;
$l5 = 0;
for ($i = 0; $i <= 10000; $i++) {
    $result = Lottery::runOnce(array(20, 10, 10, 10), array(0, 1));
    if ($result === 0)
        $l0++;
    if ($result == 1)
        $l1++;
    if ($result == 2)
        $l2++;
    if ($result == 3)
        $l3++;
    if ($result == 4)
        $l4++;
}
echo '0:' . $l0 . '<br/>1:' . $l1 . '<br/>2:' . $l2 . '<br/>3:' . $l3 . '<br/>4:' . $l4;