从数组中选择随机字符串 [英] Pick Random String From Array

问题描述

如何从数组中随机选择一个字符串，但不选择相同的字符串两次.

string[] names = { "image1.png", "image2.png", "image3.png", "image4.png", "image5.png" };

这可能吗?我正在考虑使用

return strings[random.Next(strings.Length)];

但这有可能两次返回相同的字符串.还是我错了?我是否应该使用诸如 List 之类的其他东西来完成此操作.欢迎任何反馈.

解决方案

最简单的方法(但对于大型列表来说速度较慢)是使用可调整大小的容器，例如 List 并在选择元素后将其删除.喜欢:

var names = new List{ "image1.png", "image2.png", "image3.png", "image4.png", "image5.png" };int index = random.Next(names.Count);var name = 名称[索引];名称.RemoveAt(index);返回名称；

当您的列表为空时，所有值都被选中.

一种更快的方法(尤其是当您的列表很长时)是在您的列表上使用改组算法.然后，您可以一次弹出一个值.它会更快，因为从 List 的末尾删除通常比从中间删除要快得多.至于改组，你可以看看这个问题了解更多详情.>

How do I go about picking a random string from my array but not picking the same one twice.

string[] names = { "image1.png", "image2.png", "image3.png", "image4.png", "image5.png" };

Is this possible? I was thinking about using

return strings[random.Next(strings.Length)];

But this has the possibility of returning the same string twice. Or am I wrong about this? Should I be using something else like a List to accomplish this. Any feedback is welcome.

解决方案

The simplest way (but slow for large lists) would be to use a resizeable container like List and remove an element after picking it. Like:

var names = new List<string> { "image1.png", "image2.png", "image3.png", "image4.png", "image5.png" };

int index = random.Next(names.Count);
var name = names[index];
names.RemoveAt(index);
return name;

When your list is empty, all values were picked.

A faster way (especially if your list is long) would be to use a shuffling algorithm on your list. You can then pop the values out one at a time. It would be faster because removing from the end of a List is generally much faster than removing from the middle. As for shuffling, you can take a look at this question for more details.

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