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

jsfiddle:https://jsfiddle.net/cyGwf/477/

随机整数:要获得最小值和最大值之间的随机整数,请使用以下代码

function getRandomInteger(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min;
}

随机浮点数:要获得最小值和最大值之间的随机浮点数,请使用以下代码

function getRandomFloat(min, max) {
  return Math.random() * (max - min) + min;
}

参考:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random

其他回答

jsfiddle:https://jsfiddle.net/cyGwf/477/

随机整数:要获得最小值和最大值之间的随机整数,请使用以下代码

function getRandomInteger(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min;
}

随机浮点数:要获得最小值和最大值之间的随机浮点数,请使用以下代码

function getRandomFloat(min, max) {
  return Math.random() * (max - min) + min;
}

参考:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random

如果您想覆盖负数和正数,并确保其安全,请使用以下方法:

JS解决方案:

function generateRangom(low, up) {
  const u = Math.max(low, up);
  const l = Math.min(low, up);
  const diff = u - l;
  const r = Math.floor(Math.random() * (diff + 1)); //'+1' because Math.random() returns 0..0.99, it does not include 'diff' value, so we do +1, so 'diff + 1' won't be included, but just 'diff' value will be.
  
  return l + r; //add the random number that was selected within distance between low and up to the lower limit.  
}

Java解决方案:

public static int generateRandom(int low, int up) {
        int l = Math.min(low, up);
        int u = Math.max(low, up);
        int diff = u - l;

        int r = (int) Math.floor(Math.random() * (diff + 1)); // '+1' because Math.random() returns 0..0.99, it does not include 'diff' value, so we do +1, so 'diff + 1' won't be included, but just 'diff' value will be.
  
        return l + r;//add the random number that was selected within distance between low and up to the lower limit.      
}

实例

返回1到10之间的随机数:

Math.floor((Math.random() * 10) + 1);

结果可能是:3.

试试看:这里

--

或使用lodash/descore:

_.随机(最小值,最大值)

文件:-罗达什-不受欢迎的

我发现了一种使用ES6默认参数实现这一点的新方法。它非常漂亮,因为它允许一个参数或两个参数。这里是:

function random(n, b = 0) {
    return Math.random() * (b-n) + n;
}

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