如何使用 JavaScript 从数组中选择一个随机值？
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How do I choose a random value from an array with JavaScript?
提问by don3434
Possible Duplicate:
JavaScript: Getting random value from an array
可能的重复：
JavaScript：从数组中获取随机值
I have an external js with the following line:
我有一个带有以下行的外部js：
var postmessage = "hi my favorite site is http://google.com";
but is there a way to pick a site a random from an array so like this
但是有没有办法像这样从数组中随机选择一个站点
var postmessage = "hi my favorite site is +'random'";
random= http://google.com, http://yahoo.com, http://msn.com, http://apple.com
how do i make it work?
我如何使它工作？
回答by Brian Campbell
var favorites = ["http://google.com", "http://yahoo.com", "http://msn.com", "http://apple.com"];
var favorite = favorites[Math.floor(Math.random() * favorites.length)];
var postmessage = "hi my favorite site is " + favorite;
Create an array of your sites, then pick one element from the array. You do this by choosing a random number using Math.random(), which gives you a result greater than or equal to 0 and less than 1. Multiply by the length of your array, and take the floor(that is, take just the integer part, dropping off any decimal points), so you will have a number from 0 to one less than the length of your array (which will thus be a valid index into your array). Use that result to pick an element from your array.
创建一个站点数组，然后从数组中选择一个元素。您可以通过使用 选择一个随机数来做到这一点Math.random()，这会为您提供大于或等于 0 且小于 1 的结果。乘以数组的长度，并取下地板（即，只取整数部分，下降任何小数点），因此您将得到一个比数组长度少 0 到 1 的数字（因此这将是数组的有效索引）。使用该结果从数组中选择一个元素。
回答by locrizak
var sites = new Array('http://www.google.com', "http://www.stackoverflow.com")
var postmessage = "hi my favorite site is" + sites[Math.round(Math.random()*(sites.length-1))];
First stick all of your sites in an array. Then get a random number from the array length (the -1 is because an array is zero indexed and the length that is returned starts at 1)
首先将您所有的网站放在一个数组中。然后从数组长度中获取一个随机数（-1 是因为数组的索引为零并且返回的长度从 1 开始）
回答by Naveed Ahmad
Do something like this:
做这样的事情：
function getRandomSite(){
var sites = ["google.com","bing.com","xyz.com","abc.com","example.com"];
var i = parseInt(Math.random()*(sites.length-1));
return sites[i];
};
