How could I improve this C# randomising method?

Question

I think I\'ve settled on this as the most simple and unit-testable method for randomising a list, but would be interested to hear of any improvements.

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Answer 1

You want a shuffle, and the best way to do that is the Fisher-Yates shuffle:

public static IList Randomise(IList list, int seed) 
{
    Random rng = new Random(seed); 

    List ret = new List(list);      
    int n = ret.Length;            
    while (n > 1) 
    {
        n--;                         
        int k = rng.Next(n + 1);  
        // Simple swap of variables
        T tmp = list[k];
        ret[k] = ret[n];
        ret[n] = tmp;
    }
    return ret;
}