Javascript获取具有特定数组概率的随机结果 [英] Javascript Get Random result with probability for specific array

问题描述

我有一个数组，我需要按照下面的概率随机显示输出

i have a array and i need to do it randomly show the output by probability below are my code

var shirts = [
                      ["images/fantastic-logo.png","12.65"],
                      ["images/fantastic-word.png","10.00"],
                      ["images/free-product.png","15.50"]
                      ];

        var pos = Math.floor((Math.random() * shirts.length) + 0);
        $("#image").html($("<img/>").attr("src", shirts[pos][0]));
        $(".price").html("$" + shirts[pos][1]);

我已经做了基本的math.random()使其随机显示图像，现在我需要使其具有概率显示，例如显示["images/fantastic-logo.png"，"12.65" ]为50％，["images/fantastic-word.png"，"10.00"]为25％，["images/free-product.png"，"15.50"]为25％.

i have do the basic math.random() to make it random show the image, now i need to make it show with probability, for example probability for showing ["images/fantastic-logo.png","12.65"] was 50%, ["images/fantastic-word.png","10.00"] was 25%, ["images/free-product.png","15.50"] was 25%.

感谢大家的帮助

推荐答案

一个选项是添加第三个元素，该元素指示概率的权重.

One option is add a third element which indicate the weight of probability.

在下面的示例中，fantastic-logo.png有2个代表50％，其他2个只有1个代表25％.

In the example below fantastic-logo.png has 2 to represent 50% and the other 2 only as 1 to represent 25% each.

然后创建一个4元素数组[0,0,1,2]-这表示元素0具有50％的机会.元素1的几率是25％，元素2的几率也是25％.

Then create a 4 element array [0,0,1,2] - This represent element 0 has 50% chance. element 1 has 25% chance and element 2 has 25% as well.

从新创建的数组中进行随机选择，并将该值用作位置.

Make random from the newly created array and use the value as the position.

赞:

var shirts = [
  ["images/fantastic-logo.png", "12.65", 2],
  ["images/fantastic-word.png", "10.00", 1],
  ["images/free-product.png", "15.50", 1]
];

//Create a 4 element array based on probability weight
var probability = shirts.map((v, i) => Array(v[2]).fill(i)).reduce((c, v) => c.concat(v), []);

//Random select from probability array
var pos = probability[Math.floor((Math.random() * probability.length))];

$("#image").html($("<img/>").attr("src", shirts[pos][0]));
$(".price").html("$" + shirts[pos][1]);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="image"></div>
<div class="price"></div>

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