问题
In C#, I want to have the list of 5 random numbers, that should contain unique values from 1 to 5? How can I achieve that?
for example: 1,3,2,5,4 or 2,5,1,3,4
i.e. The list must contains 5 random numbers that should be having the numbers from 1 to 5
回答1:
Random rnd = new Random();
var list = Enumerable.Range(1, 5).OrderBy(x => rnd.Next()).ToList();
回答2:
What you need is called shuffling. The Fisher–Yates shuffle I linked let you do that in linear time, that is about the best you can get.
To do that in C#, you can even implement an extension method, that will look like :
public static Random rand = new Random();
public static List<T> Shuffle<T>(this List<T> original)
{
List<T> lst = new List<T>(original);
for (int i = lst.Count - 1; i >= 0; i--)
{
int j = rand.Next(0, i + 1);
T tmp = lst[j];
lst[j] = lst[i];
lst[i] = tmp;
}
return lst;
}
and then call it with:
var shuffled = lst.Shuffle();
来源：https://stackoverflow.com/questions/18568050/how-to-get-a-list-of-random-numbers-that-should-be-unique