how to calculate difference and intersection of two sets?

[Lebesgue]

Hi,
How to calculate the difference and intersection of two sets,which are lists ?
thx.

[edgar-rft]

From inside Emacs, first evaluate:

Code: Select all

(require 'cl)

You need to evaluate (require 'cl), because the Emacs "set-difference" and "intersection" functions are defined in "cl-seq.el", that is no standard part of Emacs, then try:

• C-h f set-difference
• C-h f intersection

and click on the source links in the *Help* buffer. The source links work of course only if the Emacs sources are installed.