How to calculate difference between two sets in emacs lisp,the sets should be lists

elisp, lisp, set, set-difference

Solution

There is a `set-difference` function in the Common Lisp extensions:

elisp> (require 'cl-lib)
cl-lib
elisp> (cl-set-difference '(1 2 3) '(2 3 4))
(1)

Problem

How to calculate the difference between two sets in Emacs Lisp? The sets should be lists. The programm should be very simple and short, or else I won't understand it. I'm a newbee. Thx

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