Is there a common LISP function to compare the con

Question

In particular, I just want to ensure that two lists have the same elements, ignoring order

Answer 1

If order isn't important, you can use equal. For instance,

(equal (list 1 2) (list 1 2))

is true. Thus one way to do it would be to (sort) the list and then use equal. Note that sort is destructive so if order matters, you might want to copy it first.

Answer 2

If repeating items are not important see also SET-EXCLUSIVE-OR.

Answer 3

Sort both lists, then compare:

(equal (sort l1 #'<) (sort l2 #'<))

Answer 4

If the order isn't important you can use "equal-set":

(equal-sets (1 2)(1 2)) -> T

(equal-sets (1 2)(2 1)) -> T

(equal-sets (1 2 5)(1 2)) -> NIL

(equal-sets (1 2)(1 5 2)) -> NIL

Answer 5

(defun same-bag-p (bag1 bag2 &key (test #'eql))
  (let ((table (make-hash-table :test test)))
    (loop for key in bag1 do (incf (gethash key table 0)))
    (loop for key in bag2 do (decf (gethash key table 0)))
    (loop for val being each hash-value of table always (= val 0))))

Answer 6

(defun list= (l1 l2 &key (test #'eql))
  (loop for i in l1
     for j in l2
     always (funcall test i j)))


(list= '(1 2 "a") '(1 2 "a") :test #'equal) ;; => T
(list= '(1 2 "a") '(1 2 "a") :test #'eql) ;; => NIL