Generate numbers based on probability

This time I will bring you the precautions for generating numbers based on probability and generating numbers based on probability. The following is a practical case, let’s take a look.

js is generated according to the configured probability. The probability rules are as follows:
1------------50%

2----------------30%

3----------------15%

5------------5%

Simple code

function myRandom() {
 var rand = Math.random();
 if (rand < .5) return 1;
 if (rand < .8) return 2;
 if (rand < .95) return 3;
 return 5;
}

The more complicated

function prizeRand(oArr) {
 var sum = 0; // 总和
 var rand = 0; // 每次循环产生的随机数
 var result = 0; // 返回的对象的key
 console.log(oArr);
 // 计算总和
 for (var i in oArr) {
  sum += oArr[i][0];
 }
 // 思路就是如果设置的数落在随机数内，则返回，否则减去本次的数
 for (var i in oArr) {
  rand = Math.floor(Math.random()*sum + 1);
  if (oArr[i][0] >= rand) {
   result = oArr[i][0];
   break;
  } else {
   sum -= oArr[i][0];
  }
 }
 return result;
}
var oArr = {'5':[5, 'Mac'], '3':[15, 'iPhone'], '2':[30, 'iPad'], '1':[50, 'iWatch']};
console.log(prizeRand(oArr));

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

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