两个数字之间的Javascript随机整数

Question

我正在尝试创建一个在两个数字之间生成随机数的随机数生成器。例如，假设我想生成一个介于 4 到 10 之间的随机数，我希望它能够从 4 到 10 之间的任何数字中进行选择。这是我尝试过的：

var randNumMin = 4;
var randNumMax = 10;
var randInt = (Math.floor(Math.random() * (randNumMax - randNumMin + 1)) + randNumMin);

但是，这似乎不起作用，并生成了不在 4 到 10 之间的奇怪随机数，有些以 0 开头。正确的算法是什么？

这是我在其中实现算法的代码：

$(function() {
    $('#generateRandNums').click(function() {

        var numCount = document.getElementById("randNumCount").value;
        var randNumMin = document.getElementById("randNumMin").value;
        var randNumMax = document.getElementById("randNumMax").value;

        if (numCount.match(/^[\d]*$/ ) && randNumMin.match(/^[\d]*$/ ) && randNumMax.match(/^[\d]*$/ )) {       
            if (numCount == "" || randNumMin == "" || randNumMax == "")  {
                alert ("Please fill out all forms then try again.");

            } else {
                if (randNumMin>randNumMax) {
                    alert ("Please make sure your first number is smaller than the second, then try again.");
                } else {
                    if (randNumMin<0) {
                        alert ("Please make sure that you generate a positive number of random numbers, then try again.");
                    } else {

                        if (numCount>1) {
                            var randResult = ("You generated " + numCount + " random numbers between " + randNumMin + " and " + randNumMax + " and got the numbers ")
                            oneNumber = 0;
                        } else {
                            var randResult = ("You generated a random number between " + randNumMin + " and " + randNumMax + " and got the number ");
                            oneNumber = 1;
                        }
                        for (i=0;i<numCount;i++) {
                        //Get a random number between randNumMin and randNumMax
                        var randInt = (Math.floor(Math.random() * (randNumMax - randNumMin + 1)) + randNumMin);
                            if (i == numCount-1) {
                                if (oneNumber == 0) {
                                    randResult = (randResult + "and " + randInt + ".");
                                } else {
                                    randResult = (randResult + randInt + ".");
                                }
                            } else {
                                randResult = (randResult + randInt + ", ");
                            }
                        }
                        $("#randNumResults").val(randResult);
                    }
                }
            }
        } else {
            alert ("Make sure you only enter numbers and no spaces, then try again.");
        }

    });
});

我也尝试用这个替换 randInt 行：

var randInt = Math.floor((Math.random() * ((randNumMax + 1) - randNumMin)) + randNumMin);

还是不行。 我不确定算法是否错误，或者我将其错误地合并到函数中。感谢您的回答，谢谢。

Answer 1

Generating random whole numbers in JavaScript in a specific range?

/**
 * Returns a random number between min and max
 */
function getRandomArbitary (min, max) {
    return Math.random() * (max - min) + min;
}

/**
 * Returns a random integer between min and max
 * Using Math.round() will give you a non-uniform distribution!
 */
function getRandomInt (min, max) {
    return Math.floor(Math.random() * (max - min + 1)) + min;
}

http://roshanbh.com.np/2008/09/get-random-number-range-two-numbers-javascript.html

//function to get random number upto m
function randomXToY(minVal,maxVal,floatVal)
{
    var randVal = minVal+(Math.random()*(maxVal-minVal));
    return typeof floatVal=='undefined'?Math.round(randVal):randVal.toFixed(floatVal);
}

或

Generate random number between two numbers in JavaScript

Answer 2

您的问题是您从未将字符串转换为数字尝试添加此

if (  numCount.match(/^[\d]*$/ ) && 
    randNumMin.match(/^[\d]*$/ ) && 
    randNumMax.match(/^[\d]*$/ )){
  if (numCount === "" || randNumMin === "" || randNumMax === "")  {
    alert ("Please fill out all forms then try again.");
  } else {
    numCount=numCount-0;randNumMin=randNumMin-0;randNumMax=randNumMax-0;

另一个注意事项，您需要将检查值是否为空字符串更改为严格相等。要了解我的意思，请尝试对其中一个值使用零。 0 == ""//returns true 因为两者都是假的 0 === ""//returns false。

Answer 3

Underscore.js 对此 _.random(min,max) 有一个很好的实用程序

Answer 4

这个怎么样？

var max = 10;
var min = 4;
var random = Math.floor((Math.random() * ((max + 1) - min)) + min);

Answer 5

randojs.com 使它成为一个简单的单行：

rando(4, 10)

您只需将其添加到您的 html 文档的头部，您就可以轻松地随心所欲地做任何您想做的事情。来自数组的随机值、随机的 jquery 元素、来自对象的随机属性，甚至在需要时防止重复。

<script src="https://randojs.com/1.0.0.js"></script>