如何生成一个范围内的随机数但排除一些? [英] How can I generate a random number within a range but exclude some?

问题描述

基本上我选择0-24之间的随机数:

Basically I pick a random number between 0-24:

Math.floor(Math.random() * myArray.length); // myArray contains 25 items

假设结果是 8.现在我想得到另一个在 0-24 范围内的数字，但这次，我不想要 8.下一次，我可能会掷出 15.现在我想要再次滚动，但我不想要 8 或 15.我现在处理此问题的方式是使用 do while 循环，如果数字相同，我只需重新滚动.

Lets say it comes out to be 8. Now I want to get another number in the same range 0-24 but this time, I do not want an 8. The next time, I might roll a 15. Now I want to roll again but I don't want an 8 or 15. The way I am handling this now is by using do while loops and if the number comes out the same, I just reroll.

这是我家庭作业的一小部分，事实上，我已经让它满足所有要求，所以我想你可以说这是为了我个人的利益，所以我可以正确地写这个而不是结束每日wtf".

This is a small portion of my homework and I, in fact, have it working to meet all the requirements so I guess you could say this is for my own personal benefit so I can write this properly and not end up on "the daily wtf".

推荐答案

设置一个包含所有值的数组(如果你只做小数字，这只是一个有效的选项，比如你的例子中的 25)，像这样:

Set an array with all the values (this is only a valid option if you're only doing small numbers, like the 25 in your example), like this:

var array = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24];

然后，在 0 和数组长度之间选择一个随机数:

then, pick a random number between 0 and the array length:

var num = Math.floor(Math.random() * array.length);

从数组中删除该索引号:

var roll = array.splice(num, 1);

Javascript splice()从数组中删除索引项并将项作为数组返回.非常适合您使用.

Javascript splice() removes indexed items from an array and returns the item(s) as an array. Perfect for your use.

从卷中获取第一个索引，因为无论如何我们只删除了 1 个:

Grab the first index from the roll, since we only cut 1 out anyway:

var yourNumber = roll[ 0 ];

继续做尽可能多的卷.此外，您可能希望将原始数组存储为副本，以便轻松重置"数字.

Keep doing for as many rolls as you want. Also, you might want to store the original array as a copy so that you can "reset" the numbers easily.

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