![改组所需的IEnumerable扩展方法[重复]](http://www.mshxw.com/aiimages/31/568457.png "改组所需的IEnumerable扩展方法[重复]")
您可以使用Fisher-Yates-
Durstenfeld混洗。不需要显式地将size参数传递给方法本身，
Take如果不需要整个序列，则可以简单地进行调用：
var shuffled = originalSequence.Shuffle().Take(5);// ...public static class EnumerableExtensions{ public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source) { return source.Shuffle(new Random()); } public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source, Random rng) { if (source == null) throw new ArgumentNullException("source"); if (rng == null) throw new ArgumentNullException("rng"); return source.ShuffleIterator(rng); } private static IEnumerable<T> ShuffleIterator<T>( this IEnumerable<T> source, Random rng) { var buffer = source.ToList(); for (int i = 0; i < buffer.Count; i++) { int j = rng.Next(i, buffer.Count); yield return buffer[j]; buffer[j] = buffer[i]; } }}
