两个数字之间的Javascript随机整数

Question

我正在尝试创建一个随机数生成器,在两个数字之间生成随机数.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中选择任意数字.这是我尝试过的:

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

然而,这似乎不起作用,并产生了不在4到10之间的奇怪随机数,有些从0开始.这样做的正确算法是什么？

这是我正在实现该算法的代码:

$(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);

它仍然无法正常工作.我不确定算法是错误的还是我将错误合并到函数中.感谢您的回答.

Answer 1

在JavaScript中生成特定范围内的随机整数？

/**
 * 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);
}

要么

在JavaScript中生成两个数字之间的随机数

Answer 2

你的问题是你从未将字符串转换为数字尝试添加这个

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;

另请注意，您需要将检查值是否为空字符串更改为严格相等。要明白我的意思，请尝试使用零作为其中一个值。0 == ""//returns true因为两者都是假的0 === ""//returns false。