Sure but you didn't say that in the post, you said there are two modes only, a normal mode that contains all the words and another easier mode which has words up to 4 letters. For this you can easily create two files to load.
If you're now saying that you need to draw certain words from the list and customise it then yes you can run through each value and compare len to a variable. If I was doing this I would still use files because it sounds like a game where you know the required list of possible words before a mode begins so therefore you can create lists and load them.