root/lang/xyzzy/pci-code/site-lisp/chapter2/recommendations.l @ 30466

;; -*- mode: lisp-interaction-mode -*-

(defparameter *critics*
  '(("Lisa Rose"
     ("Lady in the Water" . 2.5)
     ("Snakes on a Plane" . 3.5)
     ("Just My Luck" . 3.0)
     ("Superman Returns" . 3.5)
     ("You, Me and Dupree" . 2.5)
     ("The Night Listener" . 3.0))
    ("Gene Seymour"
     ("Lady in the Water" . 3.0)
     ("Snakes on a Plane" . 3.5)
     ("Just My Luck" . 1.5)
     ("Superman Returns" . 5.0)
     ("The Night Listener" . 3.0)
     ("You, Me and Dupree" . 3.5))
    ("Michael Phillips"
     ("Lady in the Water" . 2.5)
     ("Snakes on a Plane" . 3.0)
     ("Superman Returns" . 3.5)
     ("The Night Listener" . 4.0))
    ("Claudia Puig"
     ("Snakes on a Plane" . 3.5)
     ("Just My Luck" . 3.0)
     ("The Night Listener" . 4.5)
     ("Superman Returns" . 4.0)
     ("You, Me and Dupree" . 2.5))
    ("Mick LaSalle"
     ("Lady in the Water" . 3.0)
     ("Snakes on a Plane" . 4.0)
     ("Just My Luck" . 2.0)
     ("Superman Returns" . 3.0)
     ("The Night Listener" . 3.0)
     ("You, Me and Dupree" . 2.0))
    ("Jack Matthews"
     ("Lady in the Water" . 3.0)
     ("Snakes on a Plane" . 4.0)
     ("The Night Listener" . 3.0)
     ("Superman Returns" . 5.0)
     ("You, Me and Dupree" . 3.5))
    ("Toby"
     ("Snakes on a Plane" . 4.5)
     ("You, Me and Dupree" . 1.0)
     ("Superman Returns" . 4.0))))

;
(defun $ (lst &rest items)
  (if items
      (apply '$ (assoc (car items) lst :test #'equal) (cdr items))
    (cdr lst)))

;($ *critics* "Lisa Rose")
;($ *critics* "Lisa Rose" "Lady in the Water")


;;; p10 2.3.1 ���[�N���b�h�����ɂ��X�R�A

(defun sim-distance (prefs person1 person2)
  ;; ��Ƃ������Ă����C�e���̃��X�g�𓾂�  (let ((si (intersection (mapcar #'car ($ prefs person1))
                          (mapcar #'car ($ prefs person2))
                          :test #'equal)))
    ;; ���҂Ƃ��]�����Ă����̂��������� 0 ���
    (if (not si)
        0
      ;; ���ׂĂ̍��̕��������킹��      (let ((sum-of-squares
             (reduce #'+ (mapcar #'(lambda (item)
                                     (expt (- ($ prefs person1 item)
                                              ($ prefs person2 item))
                                           2))
                                 si))))
        (/ 1 (1+ sum-of-squares))))))

;(sim-distance *critics* "Lisa Rose" "Gene Seymour")