How to permute C# Tuple Items?

Question

How to permute a tuple containing several string items?

The question is about if it's possible at all (having n-item tuple) — Andrejs Igumenovs, Jul 04 '15 at 14:38

score 2 · Answer 1 · edited May 23 '17 at 12:08

2

Because "6"is a very small number, it is most efficient to just write it down:

tupple1 = a,b,c
tupple2 = a,c,b
...

You can't create a program in shorter time.

If you are interested in a more genral solution however, see one of the plenty links on SO, example : Permutation algorithms in C#

edited May 23 '17 at 12:08

Community

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answered Jul 04 '15 at 14:05

DrKoch

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Well, if I have one more `string d`, then the number would be 24. – Andrejs Igumenovs Jul 04 '15 at 14:12
1

Well, then this is a different question – DrKoch Jul 04 '15 at 14:17
Should I use LINQ then? – Andrejs Igumenovs Jul 04 '15 at 14:27
@AndrejsIgumenovs, if you want help creating the `n!` permutations for an `n` element tuple, then please post a question asking for that and showing what you have achieved so far. As it stands, this is a good answer to your current bad question. – David Arno Jul 04 '15 at 14:29
Please check the links in the right column "Related". You'll find plenty answers – DrKoch Jul 04 '15 at 14:30

score 0 · Accepted Answer · answered Jul 04 '15 at 14:50

Using Tuple, manually I'm afraid. So:

var tuple = new Tuple<string, string, string>("a", "b", "c");
var combination_1 = String.Concat(tuple.Item1, tuple.Item2, tuple.Item3);
var combination_2 = String.Concat(tuple.Item1, tuple.Item3, tuple.Item2);
var combination_3 = String.Concat(tuple.Item2, tuple.Item1, tuple.Item3);
var combination_4 = String.Concat(tuple.Item2, tuple.Item3, tuple.Item1);
var combination_5 = String.Concat(tuple.Item3, tuple.Item1, tuple.Item2);
var combination_6 = String.Concat(tuple.Item3, tuple.Item2, tuple.Item1);

Using modified Eric Liperts extension method, you could do something like this:

Extension method:

public static IEnumerable<IEnumerable<T>> CartesianProduct<T>(this IEnumerable<IEnumerable<T>> sequences)
{
    IEnumerable<IEnumerable<T>> emptyProduct = new[] { Enumerable.Empty<T>() };

    return sequences.Aggregate
        ( emptyProduct, (accumulator, sequence) =>
            from accseq in accumulator
            from item in sequence
            where !accseq.Contains(item)
            select accseq.Concat(new[] { item })
        );
}

Use case:

var array = new string[] { "a", "b", "c", "d", "e" };
var result = Enumerable.Range(0, array.Length).Select(_ => array).CartesianProduct();

// Print results
foreach (var item in result)
    Console.WriteLine(String.Join("", item));

If you ever wish to get all permutations including "aaa", "aab" etc. simply remove

where !accseq.Contains(item) from extension method.

Also this way: `string[] stringArray = {tuple.Item1, tuple.Item2, ... tuple.ItemN};` (unpacking tuple object first) — Andrejs Igumenovs, Jul 04 '15 at 14:54
@AndrejsIgumenovs yeah, that's right. You could get items out of tuple into array and use the same extension method. — msmolcic, Jul 04 '15 at 14:55

How to permute C# Tuple Items?

2 Answers2