php - all string combinations in a fixed length, based on a charset

Question

I'm looking to create a function that will return every possible string within a given string length, using a charset.

As an example, a charset of "abc", and a length of 2 should allow for 9 (3 ^ 2) unique combinations:

aa, ab, ac, ba, bb, bc, ca, cb, cc

(List constructed manually)

What method could be used to create such a function?

Answer 1

You already did go about this, as we can plainly see from your example solution:

aa, ab, ac, ba, bb, bc, ca, cb, cc

What did you do in your head to come up with this solution? You had to keep a few things in mind:

1. what's the char I should start with from charset?

2. as I am constructing the output string, what's the next char from charset?

3. how many chars am I allowed to pick from charset?

4. what must I do when I've picked from charset all the chars that I'm allowed to?

5. have I exhausted charset with respect to chars I can start with? if yes, I'm finished.

Can you translate this into code? Or is this answer just too cutesy?