Calculating all possible sub-sequences of a given length (C#)

Question

If I have a sequence as follows (let\'s say it\'s an IEnumerable):

[A, B, C, D, E]

Then what\'s the cleanest way to c

Answer 1

I've had success with IanG's PermuteUtils class:

char[] items = new char[] { 'A', 'B', 'C', 'D', 'E' };

foreach (IEnumerable permutation in PermuteUtils.Permute(items, 3)) {
    Console.Write("[");
    foreach (char c in permutation) {
        Console.Write(" " + c);
    }
    Console.WriteLine(" ]");
}

Results in:

[ A B C ]
[ A B D ]
[ A B E ]
[ A C B ]
[ A C D ]
[ A C E ]
[ A D B ]
[ A D C ]
[ A D E ]
[ A E B ]
[ A E C ]
[ A E D ]
[ B A C ]
[ B A D ]
[ B A E ]
[ B C A ]
[ B C D ]
[ B C E ]
[ B D A ]
[ B D C ]
...