Listing permutations of different combination of characters

Question

The closest SO topic I found is here: Listing all permutations of a string/integer

But how would I make use of this for different sets of characters for each position in

Answer 1

If the length is fixed you could use this simple query which creates a cartesian product:

string chars = "ab";
int[] digits = { 1, 2 };
var query = from c1 in chars 
            from c2 in chars 
            from d1 in digits 
            select string.Format("{0}{1}{2}", c1, c2, d1);
string[] possibleCombinations = query.ToArray();

Result:

aa1
aa2
ab1
ab2
ba1
ba2
bb1
bb2

Edit: For what it's worth, lambda as requested(query syntax is much more readable):

possibleCombinations = chars
    .SelectMany(c1 => chars
        .SelectMany(c2 => digits
            .Select(d1 => string.Format("{0}{1}{2}", c1, c2, d1))))
    .ToArray();

If you need an approach which handles a dynamic length you could have a look at this:

Dynamic Generation of All Possible Combinations of Index of an Array