Looking at each combination in jagged array

Question

What is the fastest way to loop through each possible combination of elements in a jagged array with an unknown number of rows, and an unknown number of columns in each row?

Answer 1

This works pretty sweet:

Func>, IEnumerable>> combine = null;
combine = css =>
            from c in css.First()
            from cs in css.Skip(1).Any()
                ? combine(css.Skip(1)) 
                : new [] { Enumerable.Empty() }
            select new [] { c }.Concat(cs);

If I turn the result of running your data into a string with this:

var result =
    String.Join(
        ", ",
        combine(myArray)
            .Select(c => String.Join("", c)));

...then I get this result: ACE, ACF, ADE, ADF, BCE, BCF, BDE, BDF.

This computes very fast, but it would be interesting to know what the real world input is to see if this is fast enough.