Example of php implementing lottery program winning probability algorithm

In our daily work, we often participate in some lottery activities, so today we will share with you the PHP winning probability algorithm, which can be used for scratch cards, big turntables and other lottery algorithms. The usage is very simple. There are detailed comments instructions in the code. You can understand it at a glance. Friends who need it can refer to it.

Let’s first complete the backend PHP process. The main job of PHP is to configure the awards and the corresponding winning probability. When the front-end page clicks to flip a certain box, it will send an ajax request to the backend PHP. Then the backend PHP will configure it according to the configuration. Probability, the winning result is given through the probability algorithm, and the unwon prize information is also sent to the front-end page in JSON data format.

Let’s look at the probability calculation function first

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; 
}

The above code is a classic probability algorithm. $proArr is a preset array. Assume that the array is: array(100,200,300,400). The beginning is Screen the first number from the probability range of 1,1000 to see if it is within its occurrence probability range. If not, then subtract the probability space of the number just from the value of k. In this example Just subtract 100, which means the second number is filtered within the range of 1,900. In this way, until the end, there will always be a number that meets the requirements. It's like touching something in a box. If the first one isn't right, the second one isn't right, and the third one isn't right, then the last one must be. This algorithm is simple and very efficient. The key is that this algorithm has been applied in our previous projects, especially in projects with large amounts of data. The efficiency is very good.

Next we configure the awards through PHP.

$prize_arr = array( 
  '0' => array('id'=>1,'prize'=>'平板电脑','v'=>1), 
  '1' => array('id'=>2,'prize'=>'数码相机','v'=>5), 
  '2' => array('id'=>3,'prize'=>'音箱设备','v'=>10), 
  '3' => array('id'=>4,'prize'=>'4G优盘','v'=>12), 
  '4' => array('id'=>5,'prize'=>'10Q币','v'=>22), 
  '5' => array('id'=>6,'prize'=>'下次没准就能中哦','v'=>50), 
);

The two-dimensional array records all the prize information of this lottery, where id represents the winning level, prize represents the prize, and v represents the probability of winning. Note that v must be an integer. You can set v of the corresponding award to 0, which means that the probability of winning the award is 0. The sum of v in the array (base). The larger the base, the more accurate the probability can be reflected. . In this example, the sum of v is 100, then the probability of winning for the tablet is 1%. If the sum of v is 10,000, the probability of winning is one in ten thousand.

Every time the front-end page is requested, PHP loops through the award setting array, and obtains the drawn award id through the probability calculation function get_rand. Save the winning prizes in the array $res['yes'], and save the remaining non-winning information in $res['no'], and finally output the json number data to the front-end page.

 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 
 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;]; 
 } 
 $res[&#39;no&#39;] = $pr; 
 echo json_encode($res);

Attached is a netizen’s implementation method

/**
  * 抽奖
  * @param int $total
  */
  function getReward($total=1000)
  {
  $win1 = floor((0.12*$total)/100);
  $win2 = floor((3*$total)/100);
  $win3 = floor((12*$total)/100);
  $other = $total-$win1-$win2-$win3;
  $return = array();
  for ($i=0;$i<$win1;$i++)
  {
  $return[] = 1;
  }
  for ($j=0;$j<$win2;$j++)
  {
  $return[] = 2;
  }
  for ($m=0;$m<$win3;$m++)
  {
  $return[] = 3;
  }
  for ($n=0;$n<$other;$n++)
  {
  $return[] = &#39;谢谢惠顾&#39;;
  }
  shuffle($return);
  return $return[array_rand($return)];
  }
  $data = getReward();
  echo $data;
  ?>

Summary:

I believe that everyone will read this article through In the process of learning, I have a certain understanding of the lottery program winning probability algorithm in PHP. I hope it will be helpful to your work!

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