PHP概率，抽奖

随机数，游标卡尺。
一个大饼，随机到哪个坑里，就中哪个奖。
大转盘！
公平公正！

<?php

/**
 * 抽取礼物
 * $weight_list = [
 *       [
 *           'id' => 1,
 *           'name' => '手机',
 *           'weight' => 100
 *       ],
 *       [
 *           'id' => 2,
 *           'name' => '电脑',
 *           'weight' => 100
 *       ],
 *       [
 *           'id' => 3,
 *           'name' => '洗衣机',
 *           'weight' => 100
 *       ],
 *   ];
 * 
 */
function getPrize($weight_list) {
    foreach ($weight_list as $gv) {
        $giftWeightArr[$gv['id']] = $gv['weight'];
    }

    $result = '';
    //概率数组的总概率精度
    $sumWeight = array_sum($giftWeightArr); //计算数组中元素的和
    $luckyNum = mt_rand(1, $sumWeight);
    //概率数组循环
    $beginCursor = $endCursor = 0;
    foreach ($giftWeightArr as $id => $weight) {
        $beginCursor = $endCursor;
        $endCursor += $weight;

        if ($luckyNum > $beginCursor && $luckyNum <= $endCursor) {
            $result = $id;
            break;
        }
    }
    return $result;
}


// 获取锦鲤
function doGet() {
    $gift_bag = [
        [
            'id' => 1,
            'name' => '手机',
            'weight' => 100
        ],
        [
            'id' => 2,
            'name' => '电脑',
            'weight' => 100
        ],
        [
            'id' => 3,
            'name' => '洗衣机',
            'weight' => 100
        ]
    ];


    for ($i=0;$i<10;$i++) {
        $gid = getPrize($gift_bag); //根据概率获取奖项id
        echo $gift_bag[$gid-1]['name'].PHP_EOL;
    }

}


doGet();

string(24) "抱歉，下次就中了"
string(24) "抱歉，下次就中了"
string(24) "抱歉，下次就中了"
string(24) "抱歉，下次就中了"
string(24) "抱歉，下次就中了"
string(24) "抱歉，下次就中了"
string(24) "抱歉，下次就中了"
string(9) "小金猪"
string(24) "抱歉，下次就中了"
string(9) "小金猪"

有点意思哦！