listfreq

listfreq

(defun howmany (obj lst)
  (let ((res
		  (remove-if-not #'(lambda (x)
							 (if (equal x obj) t))
						 lst)))
	(length res)))

;; we used remove-if-not to do this instead of dolist because it was just a bit easier 

(defun uniques (lst)
  (let ((res '()))
	(dolist (x lst)
	  (setf res (adjoin x res)))
	res))

(defun listfreq (lst)
  (let ((res '()))
	(let ((vals (uniques lst)))
	  (dolist (x vals)
		(push (list x (howmany x lst)) res)))
	res))