在c#中随机化泛型列表顺序的最佳方法是什么?我在一个列表中有一个有限的75个数字集,我想随机分配一个顺序,以便为彩票类型的应用程序绘制它们。


当前回答

实现:

public static class ListExtensions
{
    public static void Shuffle<T>(this IList<T> list, Random random)
    {
        for (var i = list.Count - 1; i > 0; i--)
        {
            int indexToSwap = random.Next(i + 1);
            (list[indexToSwap], list[i]) = (list[i], list[indexToSwap]);
        }
    }
}

例子:

var random = new Random();
var array = new [] { 1, 2, 3 };
array.Shuffle(random);
foreach (var item in array) {
    Console.WriteLine(item);
}

.NET小提琴演示

其他回答

private List<GameObject> ShuffleList(List<GameObject> ActualList) {


    List<GameObject> newList = ActualList;
    List<GameObject> outList = new List<GameObject>();

    int count = newList.Count;

    while (newList.Count > 0) {

        int rando = Random.Range(0, newList.Count);

        outList.Add(newList[rando]);

        newList.RemoveAt(rando);

     

    }

    return (outList);

}

用法:

List<GameObject> GetShuffle = ShuffleList(ActualList);
    public static List<T> Randomize<T>(List<T> list)
    {
        List<T> randomizedList = new List<T>();
        Random rnd = new Random();
        while (list.Count > 0)
        {
            int index = rnd.Next(0, list.Count); //pick a random item from the master list
            randomizedList.Add(list[index]); //place it at the end of the randomized list
            list.RemoveAt(index);
        }
        return randomizedList;
    }

解决这类问题的一个非常简单的方法是在列表中使用一些随机的元素交换。

在伪代码中是这样的:

do 
    r1 = randomPositionInList()
    r2 = randomPositionInList()
    swap elements at index r1 and index r2 
for a certain number of times

通过使用元组进行交换,可以使Fisher-Yates shuffle更加简洁和富有表现力。

private static readonly Random random = new Random();

public static void Shuffle<T>(this IList<T> list)
{
    int n = list.Count;
    while (n > 1)
    {
        n--;
        int k = random.Next(n + 1);
        (list[k], list[n]) = (list[n], list[k]);
    }
}

您可以使用这个简单的扩展方法来实现这一点

public static class IEnumerableExtensions
{

    public static IEnumerable<t> Randomize<t>(this IEnumerable<t> target)
    {
        Random r = new Random();

        return target.OrderBy(x=>(r.Next()));
    }        
}

你可以通过下面的步骤来使用它

// use this on any collection that implements IEnumerable!
// List, Array, HashSet, Collection, etc

List<string> myList = new List<string> { "hello", "random", "world", "foo", "bar", "bat", "baz" };

foreach (string s in myList.Randomize())
{
    Console.WriteLine(s);
}