I'm guessing you mean "dd" and "yy" to delete/yank lines. "x" deletes a single character, what you mean extract a line?
If you learn "w", which just means advance by a word, you can combine them with your existing knowledge for much better use. So "dw" becomes delete a word, or "d3w" means delete next 3 words. "v" is also useful in conjunction with "w" / "b".