有没有办法用JavaScript生成指定范围内的随机数?

例如:指定范围从1到6,随机数可以是1、2、3、4、5或6。


当前回答

数学不是我的强项,但我一直在做一个项目,我需要在正负之间生成很多随机数。

function randomBetween(min, max) {
    if (min < 0) {
        return min + Math.random() * (Math.abs(min)+max);
    }else {
        return min + Math.random() * max;
    }
}

例如

randomBetween(-10,15)//or..
randomBetween(10,20)//or...
randomBetween(-200,-100)

当然,您也可以添加一些验证,以确保您不使用数字以外的任何内容。还要确保最小值始终小于或等于最大值。

其他回答

使用可重用的随机函数。

function randomNum(min, max) {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}
randomNum(1, 6);

其他解决方案:

(数学随机()*6|0)+1~~(数学随机()*6)+1

联机尝试

根据@Francisc的答案中的int版本添加具有固定精度版本的float:

function randomFloatFromInterval (min, max, fractionDigits) {
  const fractionMultiplier = Math.pow(10, fractionDigits)
  return Math.round(
    (Math.random() * (max - min) + min) * fractionMultiplier,
  ) / fractionMultiplier
}

so:

randomFloatFromInterval(1,3,4) // => 2.2679, 1.509, 1.8863, 2.9741, ...

对于int答案

randomFloatFromInterval(1,3,0) // => 1, 2, 3

重要的

The following code works only if the minimum value is `1`. It does not work for minimum values other than `1`.

如果你想得到一个介于1(且只有1)和6之间的随机整数,你可以计算:

const rndInt=数学地板(Math.random()*6)+1控制台日志(rndInt)

哪里:

1是起始编号6是可能结果的数量(1+start(6)-end(1))

这个简单的功能很方便,在任何情况下都可以使用(经过充分测试)。此外,结果的分布已经过充分测试,100%正确。

function randomInteger(pMin = 1, pMax = 1_000_000_000)
//Author: Axel Gauffre. 
//Here: https://stackoverflow.com/a/74636954/5171000
//Inspired by: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random#getting_a_random_number_between_two_values
//
//This function RETURNS A RANDOM INTEGER between pMin (INCLUDED) and pMax (INCLUDED).
//  - pMin and pMax should be integers.
//  - HOWEVER, if pMin and/or pMax are FLOATS, they will be ROUNDED to the NEAREST integer.
//  - NEGATIVE values ARE supported.
//  - The ORDER of the 2 arguments has NO consequence: If pMin > pMax, then pMin and pMax will simply be SWAPPED.
//  - If pMin is omitted, it will DEFAULT TO 1.
//  - If pMax is omitted, it will DEFAULT TO 1 BILLION.
//
//This function works in ANY cases (fully tested).
//Also, the distribution of the results has been fully tested and is 100% correct.
{
    pMin = Math.round(pMin);
    pMax = Math.round(pMax);
    if (pMax < pMin) { let t = pMin; pMin = pMax; pMax = t;}
    return Math.floor(Math.random() * (pMax+1 - pMin) + pMin);
}