为什么JavaScript Math.random()多次返回相同的数字 [英] Why JavaScript Math.random() returns same number multiple times

问题描述

我有一个包含两个项目的数组，我需要随机选择一个项目，但是大多数情况下，我会从数组中获得相同的项目...

I have an array with two items and I need to random a choice of this items but the most of times I get the same item from array...

查看代码:

var numbers = Array(523,3452);
var choice = numbers[Math.floor(Math.random()*numbers.length)];
console.log("Choice:", choice);

如何避免这种行为?

推荐答案

随机数可以出现在条纹中；那是随机的一部分.但是随着时间的流逝，大数定律应该取代甚至消除这些条纹.您可以通过多次运行并计数来轻松地进行测试:

Random numbers can appear in streaks; that's part of being random. But over time the law of large numbers should take over and even out those streaks. You can test that easily enough by running this a bunch of times and counting:

var numbers = Array(523,3452);
let counts = [0,0]

for (let i = 0; i < 10000; i++) {
    let choice = numbers[Math.floor(Math.random()*numbers.length)];
    if (choice ===  523) counts[0]++
    else if (choice == 3452) counts[1]++
}

// counts should be about even
console.log(counts);

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