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php随机抽奖实例分析

　　本文标签：php,随机,抽奖

本文实例讲述了php随机抽奖用法 。分享给大家供大家参考 。具体分析如下：

1. 按照设定的概率，得到随机抽奖的结果 。    

复制代码 代码如下:
<?php
/**
 * 抽奖工具
 */
class lottery_tool {
    protected static $awardsArr;
    protected static $proField = probability;
    protected static $proSum = 0;
    protected static $checkAward = false;
    const SUCCESS_CODE = 0;
    const FAIL_CODE = -1;
    //检查抽奖数据
    protected static function checkAwards(){
        if (!is_array(self::$awardsArr) || empty(self::$awardsArr)) {
            return self::$checkAward = false;
        }
        self::$proSum = 0;
        foreach (self::$awardsArr as $_key => $award) {
            self::$proSum += $award[self::$proField];
        }
        if (empty(self::$proSum)) {
            return self::$checkAward = false;
        }
        return self::$checkAward = true;
    }
    protected static function successRoll($rollKey){
        return array(code => self::SUCCESS_CODE, roll_key => $rollKey, msg => roll success);
    }
    protected static function failRoll($msg = roll fail){
        return array(code => self::FAIL_CODE, msg => $msg );
    }
    //抽奖
    public static function roll () {
        if (false == self::$checkAward) {
            return self::failRoll(awards data is not the right format!);
        }
        $result = mt_rand(0, self::$proSum);
        $proValue = 0;
        foreach (self::$awardsArr as $_key => $value) {
            $proValue += $value[self::$proField];
            if ($result <= $proValue) {
                return self::successRoll($_key);
            }
        }
        return self::failRoll(wrong);
    }
    //改变概率字段名
    public static function setProField($field = null) {
        if (!empty($field)) {
            self::$proField = $field;
        }
    }
    //设置奖品
    public static function setAwards($awards){
        self::$awardsArr = $awards;
        self::checkAwards();
    }
}

2. 示例代码：
复制代码 代码如下:
$awards = array(
    0 => array(pro => 15, info => 15%的可能性),
    1 => array(pro => 25, info => 25%的可能性),
    2 => array(pro => 40, info => 40%的可能性),
    3 => array(pro => 20, info => 20%的可能性),
    );
lottery_tool::setProField(pro);
lottery_tool::setAwards($awards);
$result = array();
for ($i = 10000; $i --;) {
    $result[] = lottery_tool::roll();
}
foreach ($result as $key => $value) {
    $awards[$value[roll_key]][num] ++;
}
echo <pre>;
var_dump($awards);

运行结果如下：

复制代码 代码如下:
array
  0 =>
    array
      pro => int 15
      info => string 15%的可能性 (length=15)
      num => int 1596
  1 =>
    array
      pro => int 25
      info => string 25%的可能性 (length=15)
      num => int 2484
  2 =>
    array
      pro => int 40
      info => string 40%的可能性 (length=15)
      num => int 3939
  3 =>
    array
      pro => int 20
      info => string 20%的可能性 (length=15)
      num => int 1981

希望本文所述对大家的php程序设计有所帮助 。