Question

I have a list

(SetQ L '(1 j 3 k 4 h 5 n 6 w))

I have to do a function Order that has a list with ‘n’ atoms at entry, it must check if each atom of that list is contained in list L and order them according to the order specified in list L, if the atom is not part of the list L then the result will be displayed

(Defun Order lst)

(SetQ L2'(w o 5 j 3))

I want to verify this:

(Order L2)

result should return:

(J 3 5 W)

Answer 1

Hints:

Earlier, you asked this question:

CLISP : Check if two elements are in order one after another in a list

This function is related to the problem because it can be used as a comparison function in a call to the standard Lisp function sort.

The Lisp function intersection can produce a list which contains only those elements of one list which appear in another. This is a set operation, so it may squash duplicates; another way is to use remove-if-not where the test predicate is a lambda function which uses member to express the idea “remove all elements of this list which are not members of that other list”.