PHP implements the big wheel lottery algorithm (code example)

This article introduces you to the PHP language to implement the big carousel lottery algorithm through specific examples. I hope it will help everyone learn PHP lottery Helps.

1. Assemble the award array;

2. Calculate the probability;

3 .Return the winning status.

The code is as follows: The winning probability 'v' can be set in the background and passed to this method. Pay attention to passing integers

function get_gift(){  
        //拼装奖项数组
        // 奖项id，奖品，概率
        $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'=>5),   
          '4' => array('id'=>5,'prize'=>'10Q币','v'=>0),   
          '5' => array('id'=>6,'prize'=>'空奖','v'=>5),   
        );   

        foreach ($prize_arr as $key => $val) {   
          $arr[$val['id']] = $val['v'];//概率数组           }    
        $rid = $this->get_rand($arr); //根据概率获取奖项id   
        $res['yes'] = $prize_arr[$rid-1]['prize']; //中奖项   
        unset($prize_arr[$rid-1]); //将中奖项从数组中剔除，剩下未中奖项   
        shuffle($prize_arr); //打乱数组顺序   
        for($i=0;$i<count($prize_arr);$i++){   
          $pr[] = $prize_arr[$i][&#39;prize&#39;];  //未中奖项数组         }   
        $res[&#39;no&#39;] = $pr;
        // var_dump($res);

        if($res[&#39;yes&#39;]!=&#39;空奖&#39;){  
            $result[&#39;status&#39;]=1;  
            $result[&#39;name&#39;]=$res[&#39;yes&#39;];  
        }else{  
            $result[&#39;status&#39;]=-1;  
            $result[&#39;msg&#39;]=$res[&#39;yes&#39;];  
        }   
        //return $result;  
        var_dump($result);
    }  

    //计算中奖概率
    function get_rand($proArr) {   
      $result = &#39;&#39;;   

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

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

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