抽奖概率 PHP

抽奖概率

<?php 

function get_rand($proArr) { 
    $result = ''; 

    //概率数组的总概率精度
    $proSum = array_sum($proArr); 

    //概率数组循环
    foreach ($proArr as $key => $proCur) { 
        $randNum = mt_rand(1, $proSum); 
        if ($randNum <= $proCur) { 
            $result = $key; 
            break; 
        } else { 
            $proSum -= $proCur; 
        } 
    } 
    unset ($proArr); 

    return $result; 
}

$prize_arr = array( 
    '0' => array('id'=>1,'prize'=>'平板电脑','v'=>0), 
    '1' => array('id'=>2,'prize'=>'数码相机','v'=>0), 
    '2' => array('id'=>3,'prize'=>'音箱设备','v'=>0), 
    '3' => array('id'=>4,'prize'=>'4G优盘','v'=>0), 
    '4' => array('id'=>5,'prize'=>'10Q币','v'=>1), 
    '5' => array('id'=>6,'prize'=>'下次没准就能中哦','v'=>100), 
);  


//code here eg:unset($prize_arr['0'])
foreach ($prize_arr as $key => $val) { 
    $arr[$val['id']] = $val['v']; 
} 

$rid = get_rand($arr); //根据概率获取奖项id

$res['yes'] = $prize_arr[$rid-1]['prize']; //中奖项
//将中奖项从数组中剔除，剩下未中奖项，如果是数据库验证，这里可以省掉
unset($prize_arr[$rid-1]); 
shuffle($prize_arr); //打乱数组顺序
for($i=0;$i<count($prize_arr);$i++){ 
    $pr[] = $prize_arr[$i]['prize']; 
} 
$res['no'] = $pr; 
echo "<pre>";
print_r($res);
// echo json_encode($res);

2. [代码]抽奖概率

<?php 

function get_rand($proArr) { 
    $result = ''; 

    //概率数组的总概率精度
    $proSum = array_sum($proArr); 

    //概率数组循环
    foreach ($proArr as $key => $proCur) { 
        $randNum = mt_rand(1, $proSum); 
        if ($randNum <= $proCur) { 
            $result = $key; 
            break; 
        } else { 
            $proSum -= $proCur; 
        } 
    } 
    unset ($proArr); 

    return $result; 
}

$prize_arr = array( 
    '0' => array('id'=>1,'prize'=>'平板电脑','v'=>0), 
    '1' => array('id'=>2,'prize'=>'数码相机','v'=>0), 
    '2' => array('id'=>3,'prize'=>'音箱设备','v'=>0), 
    '3' => array('id'=>4,'prize'=>'4G优盘','v'=>0), 
    '4' => array('id'=>5,'prize'=>'10Q币','v'=>1), 
    '5' => array('id'=>6,'prize'=>'下次没准就能中哦','v'=>100), 
);  


//code here eg:unset($prize_arr['0'])
foreach ($prize_arr as $key => $val) { 
    $arr[$val['id']] = $val['v']; 
} 

$rid = get_rand($arr); //根据概率获取奖项id

$res['yes'] = $prize_arr[$rid-1]['prize']; //中奖项
//将中奖项从数组中剔除，剩下未中奖项，如果是数据库验证，这里可以省掉
unset($prize_arr[$rid-1]); 
shuffle($prize_arr); //打乱数组顺序
for($i=0;$i<count($prize_arr);$i++){ 
    $pr[] = $prize_arr[$i]['prize']; 
} 
$res['no'] = $pr; 
echo "<pre>";
print_r($res);
// echo json_encode($res);

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