Dynamically cross-join multiple different-size collections together in Linq (C#) -

i have unknown number of buckets(collections), , each bucket having unknown number of entities

i need produce cartesian product of entities, endup single collection has arrays of entities , in each array, there 1 representetive every bucket.

so if have 5 buckets (b1..b5), , buckets b1, b2 have 1 item each, , bucket b3, b4 , b5 have 4, 8 , 10 items each, i'll have collection of 320 arrays, , each array have 5 items.

the stupud issue here, both size of buckets , number of buckets unknown @ development time.

performance not super important here, of time, buckets have 1 entity, , there times when of buckets contain 20-30 items...and i'll have 5-30 buckets

i'd love utilize linq here in someway, brain getting fried try imagine how work

you create extension method following:

public static class enumerableextensions {     public static ienumerable<tvalue []> permutations<tkey, tvalue>(this ienumerable<tkey> keys, func<tkey, ienumerable<tvalue>> selector)     {         var keyarray = keys.toarray();         if (keyarray.length < 1)             yield break;         tvalue [] values = new tvalue[keyarray.length];         foreach (var array in permutations(keyarray, 0, selector, values))             yield return array;     }      static ienumerable<tvalue []> permutations<tkey, tvalue>(tkey [] keys, int index, func<tkey, ienumerable<tvalue>> selector, tvalue [] values)     {         debug.assert(keys.length == values.length);          var key = keys[index];         foreach (var value in selector(key))         {             values[index] = value;             if (index < keys.length - 1)             {                 foreach (var array in permutations(keys, index+1, selector, values))                     yield return array;             }             else             {                 yield return values.toarray(); // clone array;             }         }     } } 

as example, used like:

    public static void testpermutations()     {         int [][] seqence = new int [][]         {             new int [] {1, 2, 3},             new int [] {101},             new int [] {201},             new int [] {301, 302, 303},         };          foreach (var array in seqence.permutations(a => a))         {             debug.writeline(array.aggregate(new stringbuilder(), (sb, i) => { if (sb.length > 0) sb.append(","); sb.append(i); return sb; }));         }     } 

and produce following output:

1,101,201,301 1,101,201,302 1,101,201,303 2,101,201,301 2,101,201,302 2,101,201,303 3,101,201,301 3,101,201,302 3,101,201,303 

is want?