随机化与.NET数组的最佳方法 [英] Best way to randomize an array with .NET

问题描述

什么是随机的。NET字符串数组的最佳方式？我的数组包含了约500串，我想创建一个新的阵列具有相同的字符串，但在一个随机顺序。

What is the best way to randomize an array of strings with .NET? My array contains about 500 strings and I'd like to create a new Array with the same strings but in a random order.

请在你的答案是C＃示例。

Please include a C# example in your answer.

推荐答案

如果你在.NET 3.5中，可以使用下面的IEnumerable冷静（VB.NET，而不是C＃，但这个想法应该是清楚的... ）：

If you're on .NET 3.5, you can use the following IEnumerable coolness (VB.NET, not C#, but the idea should be clear...):

Random rnd=new Random();
string[] MyRandomArray = MyArray.OrderBy(x => rnd.Next()).ToArray();    

编辑：好了，这里是对应的VB.NET code：

OK and here's the corresponding VB.NET code:

Dim rnd As New System.Random
Dim MyRandomArray = MyArray.OrderBy(Function() rnd.Next)

二编辑，针对言论System.Random不是线程安全和只适用于玩具的应用由于返回一个基于时间序列：在我的例子中使用，随机（）是完全线程安全的，除非你允许在其中随机数组的例程重新输入，在这种情况下，你需要像锁（MyRandomArray）反正为了不要破坏你的数据，这将保护 RND 为好。

Second edit, in response to remarks that System.Random "isn't threadsafe" and "only suitable for toy apps" due to returning a time-based sequence: as used in my example, Random() is perfectly thread-safe, unless you're allowing the routine in which you randomize the array to be re-entered, in which case you'll need something like lock (MyRandomArray) anyway in order not to corrupt your data, which will protect rnd as well.

此外，应该充分理解的是，作为System.Random熵的源不是很强。正如 MSDN文档指出，你应该使用的东西从 System.Security.Cryptography.RandomNumberGenerator 如果你做任何事情与安全相关的。例如：

Also, it should be well-understood that System.Random as a source of entropy isn't very strong. As noted in the MSDN documentation, you should use something derived from System.Security.Cryptography.RandomNumberGenerator if you're doing anything security-related. For example:

using System.Security.Cryptography;

...

RNGCryptoServiceProvider rnd = new RNGCryptoServiceProvider();
string[] MyRandomArray = MyArray.OrderBy(x => GetNextInt32(rnd)).ToArray();

...

static int GetNextInt32(RNGCryptoServiceProvider rnd)
    {
        byte[] randomInt = new byte[4];
        rnd.GetBytes(randomInt);
        return Convert.ToInt32(randomInt[0]);
    }

这篇关于随机化与.NET数组的最佳方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！