创建一个返回随机整数但具有指定分布/“权重”的Javascript函数

Question

I have an array of values: 我有一个值数组：

var my_arr = [/*all kinds of stuff*/]

I have a function that generates a random number, which I use as the index of an element in my_arr ... 我有一个生成随机数的函数，用作my_arr元素的my_arr ...

var RandomFromRange = function (min,max)
{
    return Math.floor(Math.random()*(max-min+1)+min);
};

...so I could do stuff like this: ...所以我可以做这样的事情：

my_arr[RandomFromRange(0,my_arr.length)];

What I want to do is to designate certain elements within my_arr as having "priority", so that RandomFromRange returns 5, say, 25% of the time, returns 4, 14% of the time, and returns any other number... 我想做的是将my_arr某些元素指定为具有“优先级”，以便RandomFromRange返回5（例如25％的时间），返回RandomFromRange ％的时间并返回任何其他数字...

(100 - 25 - 14)/(my_arr.length - 2)

...% of the time. ...％的时间。

As I was doing my research, I came across several posts that describe similar problems , but their answers are not in Javascript, and I, alas, don't have enough math to understand their general principles. 在进行研究时，我遇到了描述类似问题的几篇文章，但是他们的答案都没有用Javascript编写，可惜我没有足够的数学知识来理解它们的一般原理。 Any advice would be appreciated. 任何意见，将不胜感激。

Answer 1

This may not be as exact as what you are looking for, but this certainly works. 这可能与您要查找的内容不完全一样，但是确实可以。 Basically this code returns a random number specified from the min and max like yours, but only after addressing the priority numbers based on the chance given. 基本上，此代码返回一个从最小值和最大值中指定的随机数，就像您的代码一样，但是仅在根据给定的机会处理了优先级数字之后才返回。

First we gotta prioritize your priority numbers in the code. 首先，我们要优先处理代码中的优先级数字。 If there is no hit on your priority numbers, that is when we proceed to the normal RNG. 如果您的优先级号码没有任何问题，那就是我们继续进行常规的RNG。

 //priority = list of numbers as priority, //chance = the percentage //min and max are your parameters var randomFromRange = function (min,max,priority,chance) { var val = null; //initialize value to return for(var i = 0; i < priority.length; i++){ //loop through priority numbers var roll = Math.floor(Math.random()*100); //roll the dice (outputs 0-100) if(chance > roll){ ///check if the chance is greater than the roll output, if true, there's a hit. Less chance value means less likely that the chance value is greater than the roll output val = priority[i]; //make the current number in the priority loop the value to return; break; //if there's a hit, stop the loop. } else{ continue; //else, keep looping through the priority list } } //if there is no hit to any priority numbers, return a number from the min and max range if(val == null){ val = Math.floor(Math.random()*(max-min+1)+min); } //return the value and do whatever you want with it return val; }; document.getElementsByTagName('body')[0].onclick = function (){ console.log(randomFromRange(0,10,[20,30],50)); }

 <!DOCTYPE html> <html> <body style='height: 1000px; width: 100%;'></body> <script></script> </html>

This code applies a single chance on all array of priority numbers. 此代码对优先级的所有数组应用一次机会。 If you want individual chances for each number in the priority list, we gotta modify the structure and change parameters to a single array of objects that holds something like 如果您希望优先级列表中的每个数字都有机会，我们必须修改结构并将参数更改为包含以下内容的单个对象数组

var priorityList = [{num: 4, chance: 25},
                    {num: 5, chance: 12}]

etc 等等

创建一个返回随机整数但具有指定分布/“权重”的Javascript函数

问题描述

1 个解决方案

解决方案1
0 已采纳 2017-11-02 01:49:36

创建一个返回随机整数但具有指定分布/“权重”的Javascript函数

问题描述

1 个解决方案

解决方案1 0 已采纳 2017-11-02 01:49:36

解决方案1
0 已采纳 2017-11-02 01:49:36